Problems in Contraception

Earlier projections of birth rate were erroneous because of inadequate appreciation of the many and changing variables: rates of industrialization, educational levels, changes in economic activity, rates of family formation, marriage, timing of births, and so forth. Although a decline in fertility may be projected over the next few years, the rising proportion of women of child-bearing age will result in higher birth rates. Many women still have more children than they say they want, and family planning has been accepted by most American women. Although only a few women receiving oral contraceptives become hypertensive, almost all women show an increase in plasma renin activity, plasma renin substrate, and angiotensin II. Hemodynamic studies show small but consistent. increases in cardiac output and mean arterial blood pressure. The oral contraceptives have been associated with an increased risk of thromboembolic disorders and death from pulmonary embolism. The relative risk of venous thromboembolism increases with increasing dose of estrogen, leading to the recommendation that the oral contraceptives contain no more than 50 µg of mestranol or ethinyl estradiol. Survey of the processes in sperm and ovum maturation and fertilization shows many areas where other approaches to contraception may be fruitful. These include several areas of basic scientific interest: the meiotic stage of spermatogenesis, the control of follicle-stimulating hormone secretion, regulation of corpus-luteum life span and steroid synthesis, and the role of progesterone in maintaining a secretory endometrium.