For too long now, articles and reports have been scattered through the nonmedical press with one obvious purpose: to dissuade all parents, even those who need the help which the pill offers, not only for contraceptive purposes, but also for prevention of feared miscarriage, from trusting it. It therefore seems highly desirable that the effect and the mode of action of these gestagens be clearly understood.
The dissuaders employ two tactics. One aims to confound people with regard to the moral aspects of pill therapy. This method consists in publicizing fond but false theories concerning the major biological action of the pill that makes it a dependable contraceptive. Particularly, the pill's suppression of ovulation is questioned. Also, speculations are bruited that the desired effect is attributable either to a modification of the cervical mucus which prevents the entrance of spermatozoa into the uterus, or to changes in the endometrium which