Using data from the National Disease and Therapeutic Index, we estimated that between 1980 and 1984, 1.9 X 10(6) U.S. men had vasectomies. Men between the ages of 30 and 39 years, and white men, were more likely than others to undergo the procedure. Further national data on this popular procedure are needed.
We tested the hypothesis that prenatal exposure to cigarette smoke is associated with impaired fertility in adulthood. Fertility for nearly 600 couples was quantified by counting the number of noncontraception cycles required to conceive. Exposure in utero was assessed by asking couples about their parents' cigarette smoking. In contrast to data on laboratory animals, husbands and wives prenatally exposed to cigarette smoke showed no evidence of reduced fertility. In exploratory analyses, prenatal exposure to cigarette smoke was associated with semen abnormalities. Although this observation was based on small numbers, it has biologic plausibility and warrants further investigation.
The absorption, metabolism, and clearance of progesterone (P) from the peripheral circulation were investigated in five postmenopausal women after oral administration of 100 mg at 9:00 A.M. and 200 mg at 9:00 P.M. for 5 consecutive days. Mean peak plasma concentrations of P were observed 2 hours after ingestion of both the 100 and 200 mg doses and were 22.7 and 47.7 nmol/l, respectively. Of the three metabolites studied, the plasma concentrations of pregnanediol-3 alpha-glucuronide were most raised by treatment; those of 17-hydroxyprogesterone were least raised. Increases in the plasma levels of 20 alpha-dihydroprogesterone were more sustained than those of P, and the plasma concentrations remained elevated at approximately 20 nmol/l for at least 12 hours after P administration. We conclude that administration of oral P 100 mg in the morning and 200 mg at night increases the circulating concentrations of P and the biologically active metabolite 20 alpha-dihydroprogesterone, and that the duration of these increases is sufficient to evoke progestational responses in responsive end-organs.
There is consensus that smoking during pregnancy has deleterious effects upon both mother and baby. Smokers who use oral contraceptives run a greater risk of arteriosclerotic cardiovascular disease after age 35 than do nonsmokers. Smokers have more problems with osteoporosis, and lung cancer in women is on the rise and clearly associated with smoking. Yet, a real association between smoking and female infertility is difficult to find. Published data are weighted in the direction of showing no deleterious effect on fertility in the woman. Studies tend to be retrospective and not much prospective work has been done in the study of fertility in women who smoke as compared with women who do not. Harlap and Barras and Linn et al. failed to demonstrate a significant increase in the time necessary to conceive among smoking women in large studies of couple cohorts seeking conception after stopping contraception. Baird and Wilcox did report a decreased fertility among 678 women smokers. Variables are difficult to control, including age, number of cigarettes smoked, and life style. 1 of the few prospective studies is the Oxford Family Planning Association Contraceptive Study of 4104 couples interrupting contraception to attempt pregnancy (6199 attempts) between 1968 and 1983, showing a decreased fertility among smokers with a significant dose-effect relationship, but the decrease appeared to exist only for women smoking more than 16 cigarettes daily. Sperm counts, morphology, and other parameters of the semen analysis seem to be different, although even this is controversial, in men who smoke significant numbers of cigarettes. Hoidas et al. used scanning electron microsocopy with an image analysis computer to score photographs of sperm preparations, measuring head area, head perimeter, midpiece area, midpiece perimeter, and tail length, deriving a "form factor" mathematically from the area and perimeter length. The derived measurement roughly equates with roundness or regularity of the shape. The form factor is significantly different in fertile and infertile male populations, without any difference between smokers and nonsmokers. Yet, Evans et al. compared semen samples from a matched infertile group of smokers and nonsmokers and found significantly abnormal morphology in the smokers. Others have found decreased motility and count, confirmed in another study only in heavy smokers.
