n. the relative openness or lack of obstruction in a tube or vessel, such as an artery or Fallopian tube.
Checking a hormone pro?le in the woman’s blood will help in the diagnosis of ovulatory disorders like polycystic ovaries, an early menopause, anorexia or other endocrine illnesses. Ovulation itself is best assessed by ultrasound scan at mid-cycle or by a blood hormone progesterone level in the second half of the cycle.
The FALLOPIAN TUBES may be damaged or blocked in 20–30 per cent of infertile women. This is usually caused by previous pelvic infection or ENDOMETRIOSIS, where menstrual blood is thought to ?ow backwards through the fallopian tubes into the pelvis and seed with cells from the lining of the uterus in the pelvis. This process often leads to scarring of the pelvic tissues; 5–10 per cent of infertility is associated with endometriosis.
To assess the Fallopian tubes adequately a procedure called LAPAROSCOPY is performed. An ENDOSCOPE is inserted through the umbilicus and at the same time a dye is pushed through the tubes to assess their patency. The procedure is performed under a general anaesthetic.
In a few cases the mucus around the cervix may be hostile to the partner’s sperm and therefore prevent fertilisation.
Defective production is responsible for up to a quarter of infertility. It may result from the failure of the testes (see TESTICLE) to descend in early life, from infections of the testes or previous surgery for testicular torsion. The semen is analysed to assess the numbers of sperm and their motility and to check for abnormal forms.
In a few cases the genetic make-up of one partner does not allow the couple ever to achieve a pregnancy naturally.
In about 25 per cent of couples no obvious cause can be found for their infertility.
Treatment Ovulation may be induced with drugs.
In some cases damaged Fallopian tubes may be repaired by tubal surgery. If the tubes are destroyed beyond repair a pregnancy may be achieved with in vitro fertilisation (IVF) – see under ASSISTED CONCEPTION.
Endometriosis may be treated either with drugs or laser therapy, and pregnancy rates after both forms of treatment are between 40–50 per cent, depending on the severity of the disease.
Few options exist for treating male-factor infertility. These are arti?cial insemination by husband or donor and more recently in vitro fertilisation. Drug treatment and surgical repair of VARICOCELE have disappointing results.
Following investigations, between 30 and 40 per cent of infertile couples will achieve a pregnancy usually within two years.
Some infertile men cannot repair any errors in the DNA in their sperm, and it has been found that the same DNA repair problem occurs in malignant cells of some patients with cancer. It is possible that these men’s infertility might be nature’s way of stopping the propagation of genetic defects. With the assisted reproduction technique called intracytoplasmic sperm injection, some men with defective sperm can fertilise an ovum. If a man with such DNA defects fathers a child via this technique, that child could be sterile and might be at increased risk of developing cancer. (See ARTIFICIAL INSEMINATION; ASSISTED CONCEPTION.)... infertility
The principle of ?breoptics in medicine is that a light from a cold light source passes down a bundle of quartz ?bres in the endoscope to illuminate the lumen of the gastrointestinal tract or the bronchi. The re?ected light is returned to the observer’s eye via the image bundle which may contain up to 20,000 ?bres. The tip of the instrument can be angulated in both directions, and ?ngertip controls are provided for suction, air insu?ation and for water injection to clear the lens or the mucosa. The oesophagus, stomach and duodenum can be visualised; furthermore, visualisation of the pancreatic duct and direct endoscopic cannulation is now possible, as is visualisation of the bile duct. Fibreoptic colonoscopy can visualise the entire length of the colon and it is now possible to biopsy polyps or suspected carcinomas and to perform polypectomy.
The ?exible smaller ?breoptic bronchoscope has many advantages over the rigid tube, extending the range of view to all segmental bronchi and enabling biopsy of pulmonary parenchyma. Biopsy forceps can be directed well beyond the tip of the bronchoscope itself, and the more ?exible ?breoptic instrument causes less discomfort to the patient.
Fibreoptic laparoscopy is a valuable technique that allows the direct vizualisation of the abdominal contents: for example, the female pelvic organs, in order to detect the presence of suspected lesions (and, in certain cases, e?ect their subsequent removal); check on the development and position of the fetus; and test the patency of the Fallopian tubes.
(See also ENDOSCOPE; BRONCHOSCOPE; LARYNGOSCOPE; LAPAROSCOPE; COLONOSCOPE.)... fibreoptic endoscopy
Health Encyclopedia