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(British Medical Bulletin 2000, Vol. 56, No. 3)
Editors: Robert Millar, David T Baird
842 pp Price £34,95/US$57 ISBN 1-85315-458-X (p/b)
London: RSM Press for the British Council, 2000 .
This edition of the British Medical Bulletin covers infertility, contraception, sexual dysfunction and the menopause. The editors are from Edinburgh and they have ensured good Scottish representation in the 20 chapters written by 35 authors. Some of the chapters will perhaps be mainly of interest to gynaecologists and scientists specializing in infertility. But the excellent results of intracytoplasmic sperm injection for the treatment of male infertility (better than in-vitro fertilization, IVF) reported by Campbell and Irvine cannot fail to impress any of us who come into contact with infertility patients.
Of wide interest too is the section in Richard Sharpe's chapter on occupation and lifestyle factors impacting on male fertility, together with seasonal fluctuations in semen quality and quantity. Heat adversely affects the sperm counts of bakers, welders and glass-blowers as well as those who sit for long periods, such as taxi and lorry drivers, computer operators and people in wheelchairs. Exposure to constituents of plastics such as phthalates and to anabolic steroids can also reduce male fertility. Sperm counts tend to decline in the summer and are lower in men who live in urban areas.
So much is still unknown about reproduction. More than half of cases of premature ovarian failure are of unknown aetiology. Nevertheless, the new genetics is being applied to male infertility and both inherited conditions and mutations have now been clearly linked to male fertility problems. And there are ethical issues relating to intracytoplasmic sperm injection treatment, which can itself increase the chance of genetic defects. The genetics here is too technical for the general reader. There are too many abbreviations too, not all of which are spelled out when first mentioned. I spent a long time looking for what CBAVD stood for and eventually found it—congenital bilateral absence of the vas deferens.
A recurring theme in this Bulletin is the development of blood vessels and the blood flow through them. The technical achievements are truly amazing. In Professor Stuart Campbell's department pioneering work on ultrasound scanning has produced images enhanced by ‘surface rendering’ to give 3D pictures. Impressive images of the early embryo and of ovarian cysts can be obtained and tubal patency can be demonstrated by views of the flow along the fallopian tube by 3D colour power angiography. Ovarian stromal blood flow velocity is raised in polycystic ovarian syndrome. Also his team have developed monitoring of follicular function by use of colour doppler imaging to measure blood flow in the wall of the leading ovarian follicle. Changes in frequency caused when an ultrasound beam interacts with moving red cells can be measured and displayed. There is a significant rise in peak systolic velocity from the time of the luteinizing hormone surge, indicating a marked increase in blood flow during the periovulatory phase. Good blood flow in the follicle is associated with better IVF outcomes. Good subendometrial blood flow has been found to correlate with uterine receptivity to implantation. Women with poor uterine perfusion have been treated with agents such as the ubiquitous sildenafil to try to increase blood flow and so to improve IVF success rates. However, no differences in blood flow have been detected so far in those with threatened miscarriage.
A whole chapter is devoted to angiogenesis in relation to the menstrual cycle. Angiogenesis is the development of new blood vessels by endothelial cell proliferation and outgrowth from pre-existing vessels. In the ovaries, uterus and placenta the vascular endothelium is active; in contrast, the endothelium is quiescent in adults, except during wound healing and tumour growth. For instance, blood flow in the corpus luteum in the mid-luteal phase is almost the greatest of any tissue in the body. This is a promising target for manipulation of reproductive function, including contraception, and is a spin-off from research being conducted in cancer. Anti-angiogenic agents (e.g. antagonists of vascular endothelial growth factor) could inhibit follicular growth and ovulation. Targeting the luteal phase would be the most likely option, prolonged suppression of angiogenesis would risk disruptive side-effects. Other conditions that could possibly be treated this way are fibroids and endometriosis.
This British Medical Bulletin is a good source of authoritative reviews on topics in human reproduction. It will be of particular interest to specialists but general practitioners will appreciate the chapters on the combined oral contraceptive pill, emergency contraception, erectile dysfunction and hormone replacement therapy.