Return of Ovulation During the Postpartum Period

. The occurrence of ovulation was determined in 21 healthy women after full term delivery by quantitation of the serum progesterone, basal body temperature and cervical mucous ferning tests. The basal body temperature was recorded daily starting during the first week postpartum and serum progesterone estimations and cervical mucus ferning tests were performed at weekly intervals starting after the first month postpartum. All patients were followed until the first postpartum menstruation, and thereafter 18 women continued the study till the second menstruation. The women investigated breast‐fed their infants for periods ranging between one and 14 weeks. Ovulation during lactation occurred in none of the cases. After weaning, when menstruation was resumed, ovulation occurred less frequently in patients who lactated for a short period as compared to those who lactated for relatively longer. When the duration of postpartum amenorrhoea was short ovulation preceded the first menstruation less frequently than in women with relatively longer postpartum amenorrhoea. The incidence of ovulation before either the first or the second menstruation was lower in primiparae than in multi‐parae. None of 12 women aged 25 years or less ovulated before the first menstruation while 7 ovulated before the second menstruation. In women above 25 years of age, ovulation occurred in 6 out of 9 before the first menstruation and in 5 out of 6 before the second menstruation. The basal body temperature and the cervical mucous ferning tests were equally adequate to detect ovulation as the serum progesterone concentration.