Chorionic gonadotropin and progesterone levels in ectopic pregnancy.

It is assumed that one function of hCG is to preserve the developing corpus luteum and maintain pregnancy by producing progesterone and thus preventing menstrual shedding. In 8 of 17 cases of ectopic pregnancy, progesterone values were in the range of the proliferative phase of a normal cycle (0.1-1ng/ml), whereas the levels of hCG were 299-1600 mIU/ml. In 8 cases the progesterone levels were in the range of the secretory phase (2.3-6.9 ng/ml), and the hCG level was 182-5500 mIU/ml. In 1 case only was the progesterone level 15.0 ng/ml with an hCG level of 325 mIU/ml. In normal pregnancies of the same gestational age, the values of progesterone were 3.8-18.7 ng/ml, and the levels of hCG were 260-1300 mIU/ml. It seems that in addition to the level of hCG, a normal fetoplacental unit is needed for the preservation of the function of the corpus luteum.