Progesterone and estrogen secretion by puerperal human ovaries

Area of Science:

• Reproductive Endocrinology
• Obstetrics
• Gynecology

Background:

• The puerperium, the period following childbirth, involves significant hormonal shifts.
• Understanding the source and levels of key reproductive hormones is crucial for postpartum health assessment.
• The role of the corpus luteum and other ovarian tissues in hormone production after placental delivery requires further elucidation.

Purpose of the Study:

• To quantify plasma concentrations of progesterone, estrone, and estradiol.
• To compare hormone levels in peripheral circulation versus ovarian veins.
• To determine the specific contribution of the corpus luteum and other ovarian tissues to hormone secretion in the early puerperium.

Main Methods:

• Blood samples were collected from the ovarian and peripheral veins of 9 women undergoing cesarean section.
• Samples were taken 20–30 minutes after placental delivery.
• Concentrations of progesterone, estrone, and estradiol were measured using validated assays.

Main Results:

• Ovarian vein progesterone concentrations were significantly higher than peripheral or contralateral ovarian vein levels, confirming puerperal corpus luteum activity.
• Estrone concentrations did not differ significantly between ovarian and peripheral veins, suggesting minimal ovarian estrone secretion.
• Estradiol concentrations were significantly higher in ovarian veins compared to peripheral levels, indicating secretion from non-corpus luteum ovarian sources.

Conclusions:

• The puerperal corpus luteum remains active, secreting significant amounts of progesterone.
• Ovarian secretion of estradiol occurs in the early puerperium, originating from tissues other than the corpus luteum.
• Estrone secretion from the ovary is negligible in the immediate postpartum period.