Endocrine studies of lactation amenorrhea

Abstract

Lactation amenorrhea was studied in 40 lactating and 14 nonlactating postpartum patients. A 24-hour urine sample and a vaginal smear were ob tained from each patient each week until the onset of the 1st menstrual period. 3 patterns of gonadotropin excretion occurred with equal frequency in the 2 groups: 1 characterized by a continuous excretion of gonadotropins and a tendency toward prolonged atrophic vaginal smears indicating low estrogen production due to temporarily refractory ovaries 2 characterized by intermittent excretion of gonadotropins and a relatively early restoration of vaginal cornification indicating fairly responsive ovaries and 3 characterized by the absence of gonadotropins and varried vaginal epithelial patterns which seems to represent a delayed recovery of pituitary function. It is concluded that with lactation the duration of amenorrhea is prolonged because of either ovarian refractoriness or delayed recovery of pituitary gonadotropic activity.