Serum Oestrogens and Progesterone After Normal Delivery

Summary The serum levels of oestrogens and progesterone were measured in 22 normal women after delivery. The first samples were obtained within seven days of delivery and the subsequent ones at weekly intervals thereafter until the return of menstruation. During lactation the serum oestrogen levels were usually at or below the lower range for the early follicular phase of the normal menstrual cycle. After the baby was weaned oestrogen levels rose gradually. With the exception of the first three days after delivery, serum progesterone values were generally low during lactation. They rose after the baby was weaned so that serum progesterone levels within the range of the luteal maximum of the normal menstrual cycle were sometimes reached at one to two weeks before the return of menstruation.