n. the *SI unit of mass equal to 1000 grams and previously defined in terms of the international prototype kept at Sèvres, near Paris; from 20 May 2019 it is defined in terms of the Planck constant. Symbol: kg.
The large Calorie or kilocalorie, which is used in the study of dietetics and physiological processes, is the amount of heat required to raise one kilogram of water one degree centigrade in temperature. The number of Calories required to carry on the processes necessary for life and body warmth – such as the beating of the heart, the movements of the chest in breathing, and the chemical activities of the secreting glands – is, for an adult person of ordinary weight, somewhere in the neighbourhood of 1,600. For ordinary sedentary occupations an individual requires about 2,500 Calories; for light muscular work slightly over 3,000 Calories; and for hard continuous labour around 4,000 Calories daily.
Under the International System of Units (SI UNITS – see APPENDIX 6: MEASUREMENTS IN MEDICINE) the kilocalorie has been replaced by the joule, the abbreviation for which is J (1 kilocalorie=4,186·8 J). The term Calorie, however, is so well established that it has been retained in this edition. Conversion from Calories (or kilocalories) to joules is made by multiplying by 4·2 .... calorie
A high blood-cholesterol level – that is, one over 6 mmol per litre or 238 mg per 100 ml – is undesirable as there appears to be a correlation between a high blood cholesterol and ATHEROMA, the form of arterial degenerative disease associated with coronary thrombosis and high blood pressure. This is well exempli?ed in DIABETES MELLITUS and HYPOTHYROIDISM, two diseases in which there is a high blood cholesterol, sometimes going as high as 20 mmol per litre; patients with these diseases are known to be particularly prone to arterial disease. There is also a familial disease known as hypercholesterolaemia, in which members of affected families have a blood cholesterol of around 18 mmol per litre or more, and are particularly liable to premature degenerative disease of the arteries. Many experts believe that there is no ‘safe level’ and that everybody should attempt to keep their cholesterol level as low as possible.
Cholesterol exists in three forms in the blood: high-density lipoproteins (HDLs) which are believed to protect against arterial disease, and a low-density version (LDLs) and very low-density type (VLDLs), these latter two being risk factors.
The rising incidence of arterial disease in western countries in recent years has drawn attention to this relationship between high levels of cholesterol in the blood and arterial disease. The available evidence indicates that there is a relationship between blood-cholesterol levels and the amount of fat consumed; however, the blood-cholesterol level bears little relationship to the amount of cholesterol consumed, most of the cholesterol in the body being produced by the body itself.
On the other hand, diets high in saturated fatty acids – chie?y animal fats such as red meat, butter and dripping – tend to raise the blood-cholesterol level; while foods high in unsaturated fatty acids – chie?y vegetable products such as olive and sun?ower oils, and oily ?sh such as mackerel and herring – tend to lower it. There is a tendency in western society to eat too much animal fat, and current health recommendations are for everyone to decrease saturated-fat intake, increase unsaturated-fat intake, increase daily exercise, and avoid obesity. This advice is particulary important for people with high blood-cholesterol levels, with diabetes mellitus, or with a history of coronary thrombosis (see HEART, DISEASES OF). As well as a low-cholesterol diet, people with high cholesterol values or arterial disease may be given cholesterol-reducing drugs such as STATINS, but this treatment requires full clinical assessment and ongoing medical monitoring. Recent research involving the world’s largest trial into the effects of treatment to lower concentrations of cholesterol in the blood showed that routine use of drugs such as statins reduced the incidence of heart attacks and strokes by one-third, even in people with normal levels of cholesterol. The research also showed that statins bene?ted women and the over-70s.... cholesterol
Nutritional Profile Energy value (calories per serving): Moderate to high Protein: None Fat: None Saturated fat: None Cholesterol: None Carbohydrates: None (except for cordials which contain added sugar) Fiber: None Sodium: Low Major vitamin contribution: None Major mineral contribution: Phosphorus
About the Nutrients in This Food Spirits are the clear liquids produced by distilling the fermented sugars of grains, fruit, or vegetables. The yeasts that metabolize these sugars and convert them into alcohol stop growing when the concentration of alcohol rises above 12–15 percent. In the United States, the proof of an alcoholic beverage is defined as twice its alcohol content by volume: a beverage with 20 percent alcohol by volume is 40 proof. This is high enough for most wines, but not high enough for most whiskies, gins, vodkas, rums, brandies, and tequilas. To reach the concentra- tion of alcohol required in these beverages, the fermented sugars are heated and distilled. Ethyl alcohol (the alcohol in beer, wine, and spirits) boils at a lower temperature than water. When the fermented sugars are heated, the ethyl alcohol escapes from the distillation vat and condenses in tubes leading from the vat to a collection vessel. The clear liquid that collects in this vessel is called distilled spirits or, more technically, grain neutral spirits. Gins, whiskies, cordials, and many vodkas are made with spirits American whiskeys (which include bourbon, rye, and distilled from grains. blended whiskeys) and Canadian, Irish, and Scotch whiskies are all made from spirits aged in wood barrels. They get their flavor from the grains and their color from the barrels. (Some whiskies are also colored with caramel.) Vodka is made from spirits distilled and filtered to remove all flavor. By law, vodkas made in America must be made with spirits distilled from grains. Imported vodkas may be made with spirits distilled either from grains or potatoes and may contain additional flavoring agents such as citric acid or pepper. Aquavit, for example, is essentially vodka flavored with caraway seeds. Gin is a clear spirit flavored with an infusion of juniper berries and other herbs (botanicals). Cordials (also called liqueurs) and schnapps are flavored spirits; most are sweetened with added sugar. Some cordials contain cream. Rum is made with spirits distilled from sugar cane (molasses). Tequila is made with spirits distilled from the blue agave plant. Brandies are made with spirits distilled from fruit. (Arma- gnac and cognac are distilled from fermented grapes, calvados and applejack from fermented apples, kirsch from fermented cherries, slivovitz from fermented plums.) Unless they contain added sugar or cream, spirits have no nutrients other than alcohol. Unlike food, which has to be metabolized before your body can use it for energy, alcohol can be absorbed into the blood-stream directly from the gastrointestinal tract. Ethyl alcohol provides 7 calories per gram.
The Most Nutritious Way to Serve This Food The USDA /Health and Human Services Dietary Guidelines for Americans defines one drink as 12 ounces of beer, five ounces of wine, or 1.25 ounces of distilled spirits, and “moderate drinking” as two drinks a day for a man, one drink a day for a woman.
Diets That May Restrict or Exclude This Food Bland diet Lactose-free diet (cream cordials made with cream or milk) Low-purine (antigout) diet
Buying This Food Look for: Tightly sealed bottles stored out of direct sunlight, whose energy might disrupt the structure of molecules in the beverage and alter its flavor. Choose spirits sold only by licensed dealers. Products sold in these stores are manufac- tured under the strict supervision of the federal government.
Storing This Food Store sealed or opened bottles of spirits in a cool, dark cabinet.
Preparing This Food All spirits except unflavored vodkas contain volatile molecules that give the beverage its characteristic taste and smell. Warming the liquid excites these molecules and intensifies the flavor and aroma, which is the reason we serve brandy in a round glass with a narrower top that captures the aromatic molecules as they rise toward the air when we warm the glass by holding it in our hands. Whiskies, too, though traditionally served with ice in America, will have a more intense flavor and aroma if served at room temperature.
What Happens When You Cook This Food The heat of cooking evaporates the alcohol in spirits but leaves the flavoring intact. Like other alcoholic beverages, spirits should be added to a recipe near the end of the cooking time to preserve the flavor while cooking away any alcohol bite. Alcohol is an acid. If you cook it in an aluminum or iron pot, it will combine with metal ions to form dark compounds that discolor the pot and the food you are cooking. Any recipe made with spirits should be prepared in an enameled, glass, or stainless-steel pot.
Medical Uses and/or Benefits Reduced risk of heart attack. Data from the American Cancer Society’s Cancer Prevention Study 1, a 12-year survey of more than 1 million Americans in 25 states, shows that men who take one drink a day have a 21 percent lower risk of heart attack and a 22 percent lower risk of stroke than men who do not drink at all. Women who have up to one drink a day also reduce their risk of heart attack. Numerous later studies have confirmed these findings. Lower cholesterol levels. Beverage alcohol decreases the body’s production and storage of low density lipoproteins (LDLs), the protein and fat particles that carry cholesterol into your arteries. As a result, people who drink moderately tend to have lower cholesterol levels and higher levels of high density lipoproteins (HDLs), the fat and protein particles that carry cholesterol out of the body. Numerous later studies have confirmed these findings. Lower risk of stroke. In January 1999, the results of a 677-person study published by researchers at New York Presbyterian Hospital-Columbia University showed that moderate alcohol consumption reduces the risk of stroke due to a blood clot in the brain among older people (average age: 70). How alcohol prevents stroke is still unknown, but it is clear that moderate use is a key. Heavy drinkers (those who consume more than seven drinks a day) have a higher risk of stroke. People who once drank heavily, but cut their consumption to moderate levels, reduce their risk of stroke. Stimulating the appetite. Alcoholic beverages stimulate the production of saliva and the gastric acids that cause the stomach contractions we call hunger pangs. Moderate amounts of alcoholic beverages, which may help stimulate appetite, are often prescribed for geriatric patients, convalescents, and people who do not have ulcers or other chronic gastric problems that might be exacerbated by the alcohol. Dilation of blood vessels. Alcoholic beverages dilate the tiny blood vessels just under the skin, bringing blood up to the surface. That’s why moderate amounts of alcoholic beverages (0.2–1 gram per kilogram of body weight, or two ounces of whiskey for a 150-pound adult) temporarily warm the drinker. But the warm blood that flows up to the surface of the skin will cool down there, making you even colder when it circulates back into the center of your body. Then an alcohol flush will make you perspire, so you lose more heat. Excessive amounts of beverage alcohol may depress the mechanism that regulates body temperature.
Adverse Effects Associated with This Food Alcoholism. Alcoholism is an addiction disease, the inability to control one’s alcohol consumption. It is a potentially life-threatening condition, with a higher risk of death by accident, suicide, malnutrition, or acute alcohol poisoning, a toxic reaction that kills by para- lyzing body organs, including the heart. Fetal alcohol syndrome. Fetal alcohol syndrome is a specific pattern of birth defects—low birth weight, heart defects, facial malformations, learning disabilities, and mental retarda- tion—first recognized in a study of babies born to alcoholic women who consumed more than six drinks a day while pregnant. Subsequent research has found a consistent pattern of milder defects in babies born to women who drink three to four drinks a day or five drinks on any one occasion while pregnant. To date there is no evidence of a consistent pattern of birth defects in babies born to women who consume less than one drink a day while preg- nant, but two studies at Columbia University have suggested that as few as two drinks a week while pregnant may raise a woman’s risk of miscarriage. (One drink is 12 ounces of beer, five ounces of wine, or 1.25 ounces of distilled spirits.) Increased risk of breast cancer. In 2008, scientists at the National Cancer Institute released data from a seven-year survey of more than 100,000 postmenopausal women showing that even moderate drinking (one to two drinks a day) may increase by 32 percent a woman’s risk of developing estrogen-receptor positive (ER+) and progesterone-receptor positive (PR+) breast cancer, tumors whose growth is stimulated by hormones. No such link was found between consuming alcohol and the risk of developing ER-/PR- tumors (not fueled by hor- mones). The finding applies to all types of alcohol: beer, wine, and distilled spirits. Increased risk of oral cancer (cancer of the mouth and throat). Numerous studies confirm the A merican Cancer Societ y’s warn ing that men and women who consume more than t wo drinks a day are at higher risk of oral cancer than are nondrinkers or people who drink less. Increased risk of cancer of the colon and rectum. In the mid-1990s, studies at the University of Oklahoma suggested that men who drink more than five beers a day are at increased risk of rectal cancer. Later studies suggested that men and women who are heavy beer or spirits drinkers (but not those who are heavy wine drinkers) have a higher risk of colorectal cancers. Further studies are required to confirm these findings. Malnutrition. While moderate alcohol consumption stimulates appetite, alcohol abuses depresses it. In addition, an alcoholic may drink instead of eating. When an alcoholic does eat, excess alcohol in his/her body prevents absorption of nutrients and reduces the ability to synthesize new tissue. Hangover. Alcohol is absorbed from the stomach and small intestine and carried by the bloodstream to the liver, where it is oxidized to acetaldehyde by alcohol dehydrogenase (ADH), the enzyme our bodies use every day to metabolize the alcohol we produce when we digest carbohydrates. The acetaldehyde is converted to acetyl coenzyme A and either eliminated from the body or used in the synthesis of cholesterol, fatty acids, and body tis- sues. Although individuals vary widely in their capacity to metabolize alcohol, an adult of average size can metabolize the alcohol in four ounces (120 ml) whiskey in approximately five to six hours. If he or she drinks more than that, the amount of alcohol in the body will exceed the available supply of ADH. The surplus, unmetabolized alcohol will pile up in the bloodstream, interfering with the liver’s metabolic functions. Since alcohol decreases the reabsorption of water from the kidneys and may inhibit the secretion of an antidiuretic hormone, the drinker will begin to urinate copiously, losing magnesium, calcium, and zinc but retaining uric acid, which is irritating. The level of lactic acid in the body will increase, making him or her feel tired and out of sorts; the acid-base balance will be out of kilter; the blood vessels in the head will swell and throb; and the stomach, its lining irritated by the alcohol, will ache. The ultimate result is a hangover whose symptoms will disappear only when enough time has passed to allow the body to marshal the ADH needed to metabolize the extra alcohol in the person’s blood. Changes in body temperature. Alcohol dilates capillaries, tiny blood vessels just under the skin, producing a “flush” that temporarily warms the drinker. But drinking is not an effective way to stay warm in cold weather. Warm blood flowing up from the body core to the surface capillaries is quickly chilled, making you even colder when it circulates back into your organs. In addition, an alcohol flush triggers perspiration, further cooling your skin. Finally, very large amounts of alcohol may actually depress the mechanism that regulates body temperature. Impotence. Excessive drinking decreases libido (sexual desire) and interferes with the ability to achieve or sustain an erection. Migraine headache. Some alcoholic beverages contain chemicals that inhibit PST, an enzyme that breaks down certain alcohols in spirits so that they can be eliminated from the body. If they are not broken down by PST, these alcohols will build up in the bloodstream and may trigger a migraine headache. Gin and vodka appear to be the distilled spirits least likely to trigger headaches, brandy the most likely.
Food/Drug Interactions Acetaminophen (Tylenol, etc.). FDA recommends that people who regularly have three or more drinks a day consult a doctor before using acetaminophen. The alcohol/acetaminophen combination may cause liver failure. Anti-alcohol abuse drugs (disulfiram [Antabuse]). Taken concurrently with alcohol, the anti- alcoholism drug disulfiram can cause flushing, nausea, a drop in blood pressure, breathing difficulty, and confusion. The severity of the symptoms, which may var y among individu- als, generally depends on the amount of alcohol consumed and the amount of disulfiram in the body. Anticoagulants. Alcohol slows the body’s metabolism of anticoagulants (blood thinners), intensif ying the effect of the drugs and increasing the risk of side effects such as spontane- ous nosebleeds. Antidepressants. Alcohol may strengthen the sedative effects of antidepressants. Aspirin, ibuprofen, ketoprofen, naproxen and nonsteroidal anti-inflammatory drugs. Like alco- hol, these analgesics irritate the lining of the stomach and may cause gastric bleeding. Com- bining the two intensifies the effect. Insulin and oral hypoglycemics. Alcohol lowers blood sugar and interferes with the metabo- lism of oral antidiabetics; the combination may cause severe hypoglycemia. Sedatives and other central nervous system depressants (tranquilizers, sleeping pills, antide- pressants, sinus and cold remedies, analgesics, and medication for motion sickness). Alcohol intensifies the sedative effects of these medications and, depending on the dose, may cause drowsiness, sedation, respiratory depression, coma, or death. MAO inhibitors. Monoamine oxidase (M AO) inhibitors are drugs used as antidepressants or antihypertensives. They inhibit the action of natural enzymes that break down tyramine, a substance formed naturally when proteins are metabolized. Tyramine is a pressor amine, a chemical that constricts blood vessel and raises blood pressure. If you eat a food that contains tyramine while you are taking an M AO inhibitor, the pressor amine cannot be eliminated from your body and the result may be a hypertensive crisis (sustained elevated blood pressure). Brandy, a distilled spirit made from wine (which is fermented) contains tyramine. All other distilled spirits may be excluded from your diet when you are taking an M AO inhibitor because the spirits and the drug, which are both sedatives, may be hazard- ous in combination.... distilled spirits
Pregnancy lasts about 280 days and is calculated from the ?rst day of the last menstrual period – see MENSTRUATION. Pregnancy-testing kits rely on the presence of the hormone beta HUMAN CHORIONIC GONADOTROPHIN (b HCG) which is excreted in the woman’s urine as early as 30 days from the last menstrual period. The estimated date of delivery can be accurately estimated from the size of the developing fetus measured by ULTRASOUND (see also below) between seven and 24 weeks. ‘Term’ refers to the time that the baby is due; this can range from 38 weeks to 41 completed weeks.
Physical changes occur in early pregnancy – periods stop and the abdomen enlarges. The breasts swell, with the veins becoming prominent and the nipples darkening. About two in three women will have nausea with a few experiencing such severe vomiting as to require hospital admission for rehydration.
Antenatal care The aim of antenatal care is to ensure a safe outcome for both mother and child; it is provided by midwives (see MIDWIFE) and doctors. Formal antenatal care began in Edinburgh in the 1930s with the recognition that all aspects of pregnancy – normal and abnormal – warranted surveillance. Cooperation between general practitioners, midwives and obstetricians is now established, with pregnancies that are likely to progress normally being cared for in the community and only those needing special intervention being cared for in a hospital setting.
The initial visit (or booking) in the ?rst half of pregnancy will record the history of past events and the results of tests, with the aim of categorising the patients into normal or not. Screening tests including blood checks and ultrasound scans are a routine part of antenatal care. The ?rst ultrasound scan is done at about 11 weeks to date the pregnancy, with a further one done at 20 weeks – the anomaly scan – to assess the baby’s structure. Some obstetric units will check the growth of the baby with one further scan later in the pregnancy or, in the case of twin pregnancies (see below), many scans throughout. The routine blood tests include checks for ANAEMIA, DIABETES MELLITUS, sickle-cell disease and THALASSAEMIA, as well as for the blood group. Evidence of past infections is also looked for; tests for RUBELLA (German measles) and SYPHILIS are routine, whereas tests for human immunode?ciency virus (see AIDS/ HIV below) and HEPATITIS are being o?ered as optional, although there is compelling evidence that knowledge of the mother’s infection status is bene?cial to the baby.
Traditional antenatal care consists of regular appointments, initially every four weeks until 34 weeks, then fortnightly or weekly. At each visit the mother’s weight, urine and blood pressure are checked, and assessment of fetal growth and position is done by palpating the uterus. Around two-thirds of pregnancies and labours are normal: in the remainder, doctors and midwives need to increase the frequency of surveillance so as to prevent or deal with maternal and fetal problems.
Common complications of pregnancy
Some of the more common complications of pregnancy are listed below.
As well as early detection of medical complications, antenatal visits aim to be supportive and include emotional and educational care. Women with uncomplicated pregnancies are increasingly being managed by midwives and general practitioners in the community and only coming to the hospital doctors should they develop a problem. A small number will opt for a home delivery, but facilities for providing such a service are not always available in the UK.
Women requiring more intensive surveillance have their management targeted to the speci?c problems encountered. Cardiologists will see mothers-to-be with heart conditions, and those at risk of diabetes are cared for in designated clinics with specialist sta?. Those women needing more frequent surveillance than standard antenatal care can be looked after in maternity day centres. These typically include women with mildly raised blood pressure or those with small babies. Fetal medicine units have specialists who are highly skilled in ultrasound scanning and specialise in the diagnosis and management of abnormal babies still in the uterus. ECTOPIC PREGNANCY Chronic abdominal discomfort early in pregnancy may be caused by unruptured ectopic pregnancy, when, rarely, the fertilised OVUM starts developing in the Fallopian tube (see FALLOPIAN TUBES) instead of the uterus. The patient needs hospital treatment and LAPAROSCOPY. A ruptured ectopic pregnancy causes acute abdominal symptoms and collapse, and the woman will require urgent abdominal surgery. URINARY TRACT INFECTIONS These affect around 2 per cent of pregnant women and are detected by a laboratory test of a mid-stream specimen of urine. In pregnancy, symptoms of these infections do not necessarily resemble those experienced by non-pregnant women. As they can cause uterine irritability and possible premature labour (see below), it is important to ?nd and treat them appropriately. ANAEMIA is more prevalent in patients who are vegetarian or on a poor diet. Iron supplements are usually given to women who have low concentrations of HAEMOGLOBIN in their blood (less than 10.5 g/dl) or who are at risk of becoming low in iron, from bleeding, twin pregnancies and those with placenta previa (see below). ANTEPARTUM HAEMORRHAGE Early in pregnancy, vaginal bleedings may be due to a spontaneous or an incomplete therapeutic ABORTION. Bleeding from the genital tract between 24 completed weeks of pregnancy and the start of labour is called antepartum haemorrhage. The most common site is where the PLACENTA is attached to the wall of the uterus. If the placenta separates before delivery, bleeding occurs in the exposed ‘bed’. When the placenta is positioned in the upper part of the uterus it is called an abruption. PLACENTA PRAEVIA is sited in the lower part and blocks or partly blocks the cervix (neck of the womb); it can be identi?ed at about the 34th week. Ten per cent of episodes of antepartum bleeding are caused by placenta previa, and it may be associated with bleeding at delivery. This potentially serious complication is diagnosed by ultrasound scanning and may require a caesarean section (see below) at delivery. INCREASED BLOOD PRESSURE, associated with protein in the urine and swelling of the limbs, is part of a condition known as PRE-ECLAMPSIA. This occurs in the second half of pregnancy in about 1 in 10 women expecting their ?rst baby, and is mostly very mild and of no consequence to the pregnancy. However, some women can develop extremely high blood pressures which can adversely affect the fetus and cause epileptic-type seizures and bleeding disorders in the mother. This serious condition is called ECLAMPSIA. For this reason a pregnant woman with raised blood pressure or PROTEIN in her urine is carefully evaluated with blood tests, often in the maternity day assessment unit. The condition can be stopped by delivery of the baby, and this will be done if the mother’s or the fetus’s life is in danger. If the condition is milder, and the baby not mature enough for a safe delivery, then drugs can be used to control the blood pressure. MISCARRIAGE Also called spontaneous abortion, miscarriage is the loss of the fetus. There are several types:
threatened miscarriage is one in which some vaginal bleeding occurs, the uterus is enlarged, but the cervix remains closed and pregnancy usually proceeds.
inevitable miscarriage usually occurs before the 16th week and is typi?ed by extensive blood loss through an opened cervix and cramp-like abdominal pain; some products of conception are lost but the developing placental area (decidua) is retained and an operation may be necessary to clear the womb.
missed miscarriages, in which the embryo dies and is absorbed, but the decidua (placental area of uterine wall) remains and may cause abdominal discomfort and discharge of old blood.
THERAPEUTIC ABORTION is performed on more than 170,000 women annually in England and Wales. Sometimes the woman may not have arranged the procedure through the usual health-care channels, so that a doctor may see a patient with vaginal bleeding, abdominal discomfort or pain, and open cervix – symptoms which suggest that the decidua and a blood clot have been retained; these retained products will need to be removed by curettage.
Septic abortions are now much less common in Britain than before the Abortion Act (1967) permitted abortion in speci?ed circumstances. The cause is the passage of infective organisms from the vagina into the uterus, with Escherichia coli and Streptococcus faecalis the most common pathogenic agents. The woman has abdominal pain, heavy bleeding, usually fever and sometimes she is in shock. The cause is usually an incomplete abortion or one induced in unsterile circumstances. Antibiotics and curettage are the treatment. INTRAUTERINE GROWTH RETARDATION describes a slowing of the baby’s growth. This can be diagnosed by ultrasound scanning, although there is a considerable margin of error in estimates of fetal weight. Trends in growth are favoured over one-o? scan results alone. GESTATIONAL DIABETES is a condition that is more common in women who are overweight or have a family member with diabetes. If high concentrations of blood sugar are found, e?orts are made to correct it as the babies can become very fat (macrosomia), making delivery more di?cult. A low-sugar diet is usually enough to control the blood concentration of sugars; however some women need small doses of INSULIN to achieve control. FETAL ABNORMALITIES can be detected before birth using ultrasound. Some of these defects are obvious, such as the absence of kidneys, a condition incompatible with life outside the womb. These women can be o?ered a termination of their pregnancy. However, more commonly, the pattern of problems can only hint at an abnormality and closer examination is needed, particularly in the diagnosis of chromosomal deformities such as DOWN’S (DOWN) SYNDROME (trisomy 21 or presence of three 21 chromosomes instead of two).
Chromosomal abnormalities can be de?nitively diagnosed only by cell sampling such as amniocentesis (obtaining amniotic ?uid – see AMNION – from around the baby) done at 15 weeks onwards, and chorionic villus sampling (sampling a small part of the placenta) – another technique which can be done from 12 weeks onwards. Both have a small risk of miscarriage associated with them; consequently, they are con?ned to women at higher risk of having an abnormal fetus.
Biochemical markers present in the pregnant woman’s blood at di?erent stages of pregnancy may have undergone changes in those carrying an abnormal fetus. The ?rst such marker to be routinely used was a high concentration of alpha-fetol protein in babies with SPINA BIFIDA (defects in the covering of the spinal cord). Fuller research has identi?ed a range of diagnostic markers which are useful, and, in conjunction with other factors such as age, ethnic group and ultrasound ?ndings, can provide a predictive guide to the obstetrician – in consultation with the woman – as to whether or not to proceed to an invasive test. These tests include pregnancy-associated plasma protein assessed from a blood sample taken at 12 weeks and four blood tests at 15–22 weeks – alphafetol protein, beta human chorionic gonadotrophin, unconjugated oestriol and inhibin A. Ultrasound itself can reveal physical ?ndings in the fetus, which can be more common in certain abnormalities. Swelling in the neck region of an embryo in early pregnancy (increased nuchal thickness) has good predictive value on its own, although its accuracy is improved in combination with the biochemical markers. The e?ectiveness of prenatal diagnosis is rapidly evolving, the aim being to make the diagnosis as early in the pregnancy as possible to help the parents make more informed choices. MULTIPLE PREGNANCIES In the UK, one in 95 deliveries is of twins, while the prevalence of triplets is one in 10,000 and quadruplets around one in 500,000. Racial variations occur, with African women having a prevalence rate of one in 30 deliveries for twins and Japanese women a much lower rate than the UK ?gure. Multiple pregnancies occur more often in older women, and in the UK the prevalence of fertility treatments, many of these being given to older women, has raised the incidence. There is now an o?cial limit of three eggs being transferred to a woman undergoing ASSISTED CONCEPTION (gamete intrafallopian transfer, or GIFT).
Multiple pregnancies are now usually diagnosed as a result of routine ultrasound scans between 16 and 20 weeks of pregnancy. The increased size of the uterus results in the mother having more or worse pregnancy-related conditions such as nausea, abdominal discomfort, backache and varicose veins. Some congenital abnormalities in the fetus occur more frequently in twins: NEURAL TUBE defects, abnormalities of the heart and the incidence of TURNER’S SYNDROME and KLINEFELTER’S SYNDROME are examples. Such abnormalities may be detected by ultrasound scans or amniocentesis. High maternal blood pressure and anaemia are commoner in women with multiple pregnancies (see above).
The growth rates of multiple fetuses vary, but the di?erence between them and single fetuses are not that great until the later stages of pregnancy. Preterm labour is commoner in multiple pregnancies: the median length of pregnancy is 40 weeks for singletons, 37 for twins and 33 for triplets. Low birth-weights are usually the result of early delivery rather than abnormalities in growth rates. Women with multiple pregnancies require more frequent and vigilant antenatal assessments, with their carers being alert to the signs of preterm labour occurring. CEPHALOPELVIC DISPROPORTION Disparity between the size of the fetus and the mother’s pelvis is not common in the UK but is a signi?cant problem in the developing world. Disparity is classi?ed as absolute, when there is no possibility of delivery, and relative, when the baby is large but delivery (usually after a dif?cult labour) is possible. Causes of absolute disparity include: a large baby – heavier than 5 kg at birth; fetal HYDROCEPHALUS; and an abnormal maternal pelvis. The latter may be congenital, the result of trauma or a contraction in pelvic size because of OSTEOMALACIA early in life. Disproportion should be suspected if in late pregnancy the fetal head has not ‘engaged’ in the pelvis. Sometimes a closely supervised ‘trial of labour’ may result in a successful, if prolonged, delivery. Otherwise a caesarean section (see below) is necessary. UNUSUAL POSITIONS AND PRESENTATIONS OF THE BABY In most pregnant women the baby ?ts into the maternal pelvis head-?rst in what is called the occipito-anterior position, with the baby’s face pointing towards the back of the pelvis. Sometimes, however, the head may face the other way, or enter the pelvis transversely – or, rarely, the baby’s neck is ?exed backwards with the brow or face presenting to the neck of the womb. Some malpositions will correct naturally; others can be manipulated abdominally during pregnancy to a better position. If, however, the mother starts labour with the baby’s head badly positioned or with the buttocks instead of the head presenting (breech position), the labour will usually be longer and more di?cult and may require intervention using special obstetric forceps to assist in extracting the baby. If progress is poor and the fetus distressed, caesarean section may be necessary. HIV INFECTION Pregnant women who are HIV positive (see HIV; AIDS/HIV) should be taking antiviral drugs in the ?nal four to ?ve months of pregnancy, so as to reduce the risk of infecting the baby in utero and during birth by around 50 per cent. Additional antiviral treatment is given before delivery; the infection risk to the baby can be further reduced – by about 40 per cent – if delivery is by caesarean section. The mother may prefer to have the baby normally, in which case great care should be taken not to damage the baby’s skin during delivery. The infection risk to the baby is even further reduced if it is not breast fed. If all preventive precautions are taken, the overall risk of the infant becoming infected is cut to under 5 per cent.
Premature birth This is a birth that takes place before the end of the normal period of gestation, usually before 37 weeks. In practice, however, it is de?ned as a birth that takes place when the baby weighs less than 2·5 kilograms (5••• pounds). Between 5 and 10 per cent of babies are born prematurely, and in around 40 per cent of premature births the cause is unknown. Pre-eclampsia is the most common known cause; others include hypertension, chronic kidney disease, heart disease and diabetes mellitus. Multiple pregnancy is another cause. In the vast majority of cases the aim of management is to prolong the pregnancy and so improve the outlook for the unborn child. This consists essentially of rest in bed and sedation, but there are now several drugs, such as RITODRINE, that may be used to suppress the activity of the uterus and so help to delay premature labour. Prematurity was once a prime cause of infant mortality but modern medical care has greatly improved survival rates in developing countries.
Labour Also known by the traditional terms parturition, childbirth or delivery, this is the process by which the baby and subsequently the placenta are expelled from the mother’s body. The onset of labour is often preceded by a ‘show’ – the loss of the mucus and blood plug from the cervix, or neck of the womb; this passes down the vagina to the exterior. The time before the beginning of labour is called the ‘latent phase’ and characteristically lasts 24 hours or more in a ?rst pregnancy. Labour itself is de?ned by regular, painful contractions which cause dilation of the neck of the womb and descent of the fetal head. ‘Breaking of the waters’ is the loss of amniotic ?uid vaginally and can occur any time in the delivery process.
Labour itself is divided into three stages: the ?rst is from the onset of labour to full (10 cm) dilation of the neck of the womb. This stage varies in length, ideally taking no more than one hour per centimetre of dilation. Progress is monitored by regular vaginal examinations, usually every four hours. Fetal well-being is observed by intermittent or continuous monitoring of the fetal heart rate in relation to the timing and frequency of the contractions. The print-out is called a cardiotocograph. Abnormalities of the fetal heart rate may suggest fetal distress and may warrant intervention. In women having their ?rst baby (primigravidae), the common cause of a slow labour is uncoordinated contractions which can be overcome by giving either of the drugs PROSTAGLANDIN or OXYTOCIN, which provoke contractions of the uterine muscle, by an intravenous drip. Labours which progress slowly or not at all may be due to abnormal positioning of the fetus or too large a fetus, when prostaglandin or oxytocin is used much more cautiously.
The second stage of labour is from full cervical dilation to the delivery of the baby. At this stage the mother often experiences an irresistible urge to push the baby out, and a combination of strong coordinated uterine contractions and maternal e?ort gradually moves the baby down the birth canal. This stage usually lasts under an hour but can take longer. Delay, exhaustion of the mother or distress of the fetus may necessitate intervention by the midwife or doctor. This may mean enlarging the vaginal opening with an EPISIOTOMY (cutting of the perineal outlet – see below) or assisting the delivery with specially designed obstetric forceps or a vacuum extractor (ventouse). If the cervix is not completely dilated or open and the head not descended, then an emergency caesarean section may need to be done to deliver the baby. This procedure involves delivering the baby and placenta through an incision in the mother’s abdomen. It is sometimes necessary to deliver by planned or elective caesarean section: for example, if the placenta is low in the uterus – called placenta praevia – making a vaginal delivery dangerous.
The third stage occurs when the placenta (or afterbirth) is delivered, which is usually about 10–20 minutes after the baby. An injection of ergometrine and oxytocin is often given to women to prevent bleeding.
Pain relief in labour varies according to the mother’s needs. For uncomplicated labours, massage, reassurance by a birth attendant, and a warm bath and mobilisation may be enough for some women. However, some labours are painful, particularly if the woman is tired or anxious or is having her ?rst baby. In these cases other forms of analgesia are available, ranging from inhalation of NITROUS OXIDE GAS, injection of PETHIDINE HYDROCHLORIDE or similar narcotic, and regional local anaesthetic (see ANAESTHESIA).
Once a woman has delivered, care continues to ensure her and the baby’s safety. The midwives are involved in checking that the uterus returns to its normal size and that there is no infection or heavy bleeding, as well as caring for stitches if needed. The normal blood loss after birth is called lochia and generally is light, lasting up to six weeks. Midwives o?er support with breast feeding and care of the infant and will visit the parents at home routinely for up to two weeks.
Some complications of labour All operative deliveries in the UK are now done in hospitals, and are performed if a spontaneous birth is expected to pose a bigger risk to the mother or her child than a specialist-assisted one. Operative deliveries include caesarean section, forceps-assisted deliveries and those in which vacuum extraction (ventouse) is used. CAESAREAN SECTION Absolute indications for this procedure, which is used to deliver over 15 per cent of babies in Britain, are cephalopelvic disproportion and extensive placenta praevia, both discussed above. Otherwise the decision to undertake caesarean section depends on the clinical judgement of the specialist and the views of the mother. The rise in the proportion of this type of intervention (from 5 per cent in the 1930s to its present level of over 23 per cent
P
of the 600,000 or so annual deliveries in England) has been put down to defensive medicine
– namely, the doctor’s fear of litigation (initiated often because the parents believe that the baby’s health has suffered because the mother had an avoidably di?cult ‘natural’ labour). In Britain, over 60 per cent of women who have had a caesarean section try a vaginal delivery in a succeeding pregnancy, with about two-thirds of these being successful. Indications for the operation include:
absolute and relative cephalopelvic disproportion.
placenta previa.
fetal distress.
prolapsed umbilical cord – this endangers the viability of the fetus because the vital supply of oxygen and nutrients is interrupted.
malpresentation of the fetus such as breech or transverse lie in the womb.
unsatisfactory previous pregnancies or deliveries.
a request from the mother.
Caesarean sections are usually performed using regional block anaesthesia induced by a spinal or epidural injection. This results in loss of feeling in the lower part of the body; the mother is conscious and the baby not exposed to potential risks from volatile anaesthetic gases inhaled by the mother during general anaesthesia. Post-operative complications are higher with general anaesthesia, but maternal anxiety and the likelihood that the operation might be complicated and di?cult are indications for using it. A general anaesthetic may also be required for an acute obstetric emergency. At operation the mother’s lower abdomen is opened and then her uterus opened slowly with a transverse incision and the baby carefully extracted. A transverse incision is used in preference to the traditional vertical one as it enables the woman to have a vaginal delivery in any future pregnancy with a much smaller risk of uterine rupture. Women are usually allowed to get up within 24 hours and are discharged after four or ?ve days. FORCEPS AND VENTOUSE DELIVERIES Obstetric forceps are made in several forms, but all are basically a pair of curved blades shaped so that they can obtain a purchase on the baby’s head, thus enabling the operator to apply traction and (usually) speed up delivery. (Sometimes they are used to slow down progress of the head.) A ventouse or vacuum extractor comprises an egg-cup-shaped metal or plastic head, ranging from 40 to 60 mm in diameter with a hollow tube attached through which air is extracted by a foot-operated vacuum pump. The instrument is placed on the descending head, creating a negative pressure on the skin of the scalp and enabling the operator to pull the head down. In mainland Europe, vacuum extraction is generally preferred to forceps for assisting natural deliveries, being used in around 5 per cent of all deliveries. Forceps have a greater risk of causing damage to the baby’s scalp and brain than vacuum extraction, although properly used, both types should not cause any serious damage to the baby.
Episiotomy Normal and assisted deliveries put the tissues of the genital tract under strain. The PERINEUM is less elastic than the vagina and, if it seems to be splitting as the baby’s head
moves down the birth canal, it may be necessary to cut the perineal tissue – a procedure called an episiotomy – to limit damage. This is a simple operation done under local anaesthetic. It should be done only if there is a speci?c indication; these include:
to hasten the second stage of labour if the fetus is distressed.
to facilitate the use of forceps or vacuum extractor.
to enlarge a perineum that is restricted because of unyielding tissue, perhaps because of a scar from a previous labour. Midwives as well as obstetricians are trained
to undertake and repair (with sutures) episiotomies.
(For organisations which o?er advice and information on various aspects of childbirth, including eclampsia, breast feeding and multiple births, see APPENDIX 2: ADDRESSES: SOURCES OF INFORMATION, ADVICE, SUPPORT AND SELF-HELP.)... pregnancy and labour
Normally, a young child requires a smaller dose than an adult. There are, however, other factors than age to be taken into consideration. Thus, children are more susceptible than adults to some drugs such as MORPHINE, whilst they are less sensitive to others such as ATROPINE. The only correct way to calculate a child’s dose is by reference to texts supplying a recommended dose in milligrams per kilogram. However, many reference texts simply quote doses for certain age-ranges.
Old people, too, often show an increased susceptibility to drugs. This is probably due to a variety of factors, such as decreased weight; diminished activity of the tissues and therefore diminished rate at which a drug is utilised; and diminished activity of the KIDNEYS resulting in decreased rate of excretion of the drug.
Weight and sex have both to be taken into consideration. Women require slightly smaller doses than men, probably because they tend to be lighter in weight. The e?ect of weight on dosage is partly dependent on the fact that much of the extra weight of a heavy individual is made up of fatty tissue which is not as active as other tissues of the body. In practice, the question of weight seldom makes much di?erence unless the individual is grossly over- or underweight.
Idiosyncrasy occasionally causes drugs administered in the ordinary dose to produce unexpected effects. Thus, some people are but little affected by some drugs, whilst in others, certain drugs – for example, psychoactive preparations such as sedatives – produce excessive symptoms in normal or even small doses. In some cases this may be due to hypersensitivity, or an allergic reaction, to the drug, which is a possibility that must always be borne in mind
(e.g. with PENICILLIN). An individual who is known to be allergic to a certain medication is strongly advised to carry a card to this e?ect, and always to inform medical and dental practitioners and/or a pharmacist before accepting a new prescription or buying an over-the-counter preparation.
Habitual use of a drug is perhaps the in?uence that causes the greatest increase in the dose necessary to produce the requisite e?ect. The classical example of this is with OPIUM and its derivatives.
Disease may modify the dose of medicines. This can occur in several ways. Thus, in serious illnesses the patient may be more susceptible to drugs, such as narcotics, that depress tissue activity, and therefore smaller doses must be given. Again, absorption of the drug from the gut may be slowed up by disease of the gut, or its e?ect may be enhanced if there is disease of the kidneys, interfering with the excretion of the drug.
Fasting aids the rapidity of absorption of drugs, and also makes the body more susceptible to their action. Partly for this reason, as well as to avoid irritation of the stomach, it is usual to prescribe drugs to be taken after meals, and diluted with water.
Combination of drugs is to be avoided if possible as it is often di?cult to assess what their combined e?ect may be. In some cases they may have a mutually antagonistic e?ect, which means that the patient will not obtain full bene?t. Sometimes a combination may have a deleterious e?ect.
Form, route and frequency of administration Drugs are now produced in many forms, though tablets are the most common and, usually, convenient. In Britain, medicines are given by mouth whenever possible, unless there is some degree of urgency, or because the drug is either destroyed in, or is not absorbed from, the gut. In these circumstances, it is given intravenously, intra-muscularly or subcutaneously. In some cases, as in cases of ASTHMA or BRONCHITIS, the drug may be given in the form of an inhalant (see INHALANTS), in order to get the maximum concentration at the point where it is wanted: that is, in the lungs. If a local e?ect is wanted, as in cases of diseases of the skin, the drug is applied topically to the skin. In some countries there is a tendency to give medicines in the form of a suppository which is inserted in the rectum.
Recent years have seen developments whereby the assimilation of drugs into the body can be more carefully controlled. These include, for example, what are known as transdermals, in which drugs are built into a plaster that is stuck on the skin, and the drug is then absorbed into the body at a controlled rate. This method is now being used for the administration of GLYCERYL TRINITRATE in the treatment of ANGINA PECTORIS, and of hyoscine hydrobromide in the treatment of MOTION (TRAVEL) SICKNESS. Another is a new class of implantable devices. These are tiny polymers infused with a drug and implanted just under the skin by injection. They can be tailored so as to deliver drugs at virtually any rate – from minutes to years. A modi?cation of these polymers now being investigated is the incorporation of magnetic particles which allow an extra burst of the incorporated drug to be released in response to an oscillating magnetic ?eld which is induced by a magnetic ‘watch’ worn by the patient. In this way the patient can switch on an extra dose of drug when this is needed: insulin, for instance, in the case of diabetics. In yet another new development, a core of drug is enclosed in a semi-permeable membrane and is released in the stomach at a given rate. (See also LIPOSOMES.)... dosage
Haemoglobin exists in two forms: simple haemoglobin, found in venous blood; and oxy-haemoglobin, which is a loose compound with oxygen, found in arterial blood after the blood has come into contact with the air in the lungs. This oxyhaemoglobin is again broken down as the blood passes through the tissues, which take up the oxygen for their own use. This is the main function of haemoglobin: to act as a carrier of oxygen from the lungs to all the tissues of the body. When the haemoglobin leaves the lungs, it is 97 per cent saturated with oxygen; when it comes back to the lungs in the venous blood, it is 70 per cent saturated. The oxygen content of 100 millilitres of blood leaving the lungs is 19·5 millilitres, and that of venous blood returning to the lungs, 14·5 millilitres. Thus, each 100 millilitres of blood delivers 5 millilitres of oxygen to the tissues of the body. Human male blood contains 13–18 grams of haemoglobin per 100 millilitres; in women, there are 12–16 grams per 100 millilitres. A man weighing 70 kilograms (154 pounds) has around 770 grams of haemoglobin circulating in his red blood corpuscles.... haemoglobin
Grade of obesity
BMI (W/H2) III >40 II 30–40 I 25–29·9 not obese <25
Causes Whatever the causes of obesity, the fact remains that energy intake (in the form of food and drink) must exceed energy output (in the form of activity and exercise) over a suf?ciently long period of time.
Obesity tends to aggregate in families. This has led to the suggestion that some people inherit a ‘thrifty’ gene which predisposes them to obesity in later life by lowering their energy output. Indeed, patients often attribute their obesity to such a metabolic defect. Total energy output is made up of the resting metabolic rate (RMR), which represents about 70 per cent of the total; the energy cost of physical activity; and thermogenesis, i.e. the increase in energy output in response to food intake, cold exposure, some drugs and psychological in?uences. In general, obese people are consistently found to have a higher RMR and total energy output, per person – and also when expressed against fat-free mass – than do their lean counterparts. Most obese people do not appear to have a reduced capacity for thermogenesis. Although a genetic component to obesity remains a possibility, it is unlikely to be great or to prevent weight loss from being possible in most patients by reducing energy intake. Environmental in?uences are believed to be more important in explaining the familial association in obesity.
An inactive lifestyle plays a minor role in the development of obesity, but it is unclear whether people are obese because they are inactive or are inactive because they are obese. For the majority of obese people, the explanation must lie in an excessive energy intake. Unfortunately, it is di?cult to demonstrate this directly since the methods used to assess how much people eat are unreliable. For most obese people it seems likely that the defect lies in their failure to regulate energy intake in response to a variety of cognitive factors (e.g. ease of ?tting of clothes) in the long term.
Unfortunately, it can be possible to identify by the time of their ?rst birthday, many of the children destined to be obese.
Rarely, obesity has an endocrine basis and is caused by hypothyroidism (see under THYROID GLAND, DISEASES OF), HYPOPITUITARISM, HYPOGONADISM or CUSHING’S SYNDROME.
Symptoms Obesity has adverse effects on MORBIDITY and mortality (see DEATH RATE) which are greatest in young adults and increase with the severity of obesity. It is associated with an increased mortality and/or morbidity from cardiovascular disease, non-insulin-dependent diabetes mellitus, diseases of the gall-bladder, osteoarthritis, hernia, gout and possibly certain cancers (i.e. colon, rectum and prostate in men, and breast, ovary, endometrium and cervix in women). Menstrual irregularities and ovulatory failure are often experienced by obese women. Obese people are also at greater risk when they undergo surgery. With the exception of gallstone formation, weight loss will reduce these health risks.
Treatment Creation of an energy de?cit is essential for weight loss to occur, so the initial line of treatment is a slimming diet. An average de?cit of 1,000 kcal/day (see CALORIE) will produce a loss of 1 kg of fat/week and should be aimed for. Theoretically, this can be achieved by increasing energy expenditure or reducing energy intake. In practice, a low-energy diet is the usual form of treatment since attempts to increase energy expenditure, either by physical exercise or a thermogenic drug, are relatively ine?ective.
Anorectic drugs, gastric stapling and jaw-wiring are sometimes used to treat severe obesity. They are said to aid compliance with a low-energy diet by either reducing hunger (anorectic drugs) or limiting the amount of food the patient can eat. Unfortunately, the long-term e?ectiveness of gastric stapling is not known, and it is debatable whether the modest reduction in weight achieved by use of anorectic drugs is worthwhile – although a new drug, ORLISTAT, is becoming available that reduces the amount of fat absorbed from food in the gastrointestinal tract. For some grossly obese patients, jaw-wiring can be helpful, but a regain of weight once the wires are removed must be prevented. These procedures carry a risk, so should be done only if an individual’s health is in danger.... obesity
The gray is the unit of radiation that is actually absorbed by any tissue or substance as a result of exposure to radiation. 1 Gy is the absorption of 1 joule of energy (from gamma radiation or X-rays) per kilogram of irradiated matter. The gray supersedes an older unit called the rad (1 Gy = 100 rads).
Because some types of radiation affect biological organisms more than others, the sievert is used as a measure of the impact of an absorbed dose. It uses additional factors, such as the kind of radiation and its energy, to quantify the effects on the body of equivalent amounts of different types of absorbed energy. The sievert replaces an older unit, the rem (1 Sv=100 rems).... radiation unit
Weight loss or weight gain occurs if the net balance is disturbed.
Weight can be compared with standardized charts for height, age, and sex. At all ages, divergence from the normal weight for height may have medical implications. For example, if weight is below 80 per cent of the standard weight for height, the individual’s nutrition is probably inadequate as a result of poor diet or disease, and if 20 per cent above the standard, he or she is considered to be suffering from obesity. An alternative method of assessment is use of the body mass index (, or Quetelet’s index), obtained by dividing weight in kilograms by the square of height in metres. A healthy weight is 20–25 ; a of greater than 25 indicates that a person is overweight. weight loss This occurs any time there is a decrease in energy intake compared with energy expenditure. The decrease may be due to deliberate weight reduction or a change in diet or activity level. It may also be a symptom of a disorder. Unexplained weight loss should always be investigated by a doctor.
Many diseases disrupt the appetite, which may lead to weight loss. Depression reduces the motivation to eat, peptic ulcer causes pain and possible food avoidance, and some kidney disorders cause loss of appetite due to the effect of uraemia. In anorexia nervosa and bulimia, complex psychological factors affect an individual’s eating pattern.
Digestive disorders, such as gastroenteritis, lead to weight loss through vomiting. Cancer of the oesophagus (see oesophagus, cancer of) and stomach cancer cause loss of weight, as does malabsorption of nutrients in certain disorders of the intestine or pancreas.
Some disorders cause weight loss by increasing the rate of metabolic activity in cells. Examples are any type of cancer, chronic infection such as tuberculosis, and hyperthyroidism. Untreated diabetes mellitus also causes weight loss due to a number of factors.... weight
mole1 n. the *SI unit of amount of substance, equal to the amount of substance that contains as many elementary units as there are atoms in 0.012 kilograms of carbon-12. The elementary units, which must be specified, may be atoms, molecules, ions, electrons, etc., or a specified group of such entities. One mole of a compound has a mass equal to its molecular weight expressed in grams. Symbol: mol.
mole2 n. a nonmalignant collection of pigmented cells in the skin. Moles are rare in infancy, increase in numbers during childhood and especially in adolescence, but decline in numbers in old age. They vary widely in appearance, being flat or raised, smooth or hairy. Changes in the shape, colour, etc., of moles in adult life should be investigated as this may be an early sign of malignant *melanoma. Medical name: pigmented naevus. See also atypical mole syndrome.... molar solution
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