Abstract

PIP: The secretion of progesterone (P) and relaxin (R):by the human corpus luteum at midpregnancy and at term was studied in 19 women, 6 of whom had their pregnancies terminated by hysterotomy at 14-18 weeks and 13 whose pregnancies went to term and were delivered by Caesarean section. Luteectomies were performed on 6 of the women at the time of Caesarean section. P and R levels were measured. R section correlated well with luteal P secretion. After Caesarean section at term the decline in serum P was parallel to that observed after hysterotomya at midtrimester. Absolute levels of P are higher at term. P decline after luteectomy was precipitous compared with Caesarean section. Results indicate that the corpus luteum in the human remains active throughout pregnancy.