"On the 50th birthday of the pill, it is appropriate to recall the milestones which have led to its development and evolution during the last five decades. The main contraceptive effect of the pill being inhibition of ovulation, it may be called a small miracle that this drug was developed long before the complex regulation of ovulation and the menstrual cycle was elucidated. Another stumbling block on its way was the hostile climate with regard to contraception that prevailed at the time."
January 1, 1970
https://en.wikiquote.org/wiki/Hormonal_birth_control