Placental and ovarian hormones in anembryonic pregnancy

The circulating levels of human chorionic gonadotrophin (HCG),pregnancy-associated plasma protein-A (PAPP-A), Schwangerschaftprotein 1 (SP-1), oestradiol and progesterone were measuredin 81 pregnant patients between 4 and 11 weeks gestation, followingin-vitro fertilization and embryo transfer. The patients weredivided as follows: singleton anembryonic pregnancies, n = 22;singleton pregnancies which spontaneously aborted followingthe demonstration of fetal heart activity, n = 7; and normalsingleton pregnancies, n = 52. The levels of all substancesmeasured were significantly reduced in women with anembryoniccompared to those with singleton pregnancies which proceededto term. The serum levels of SP-1, weeks 6–8 (P < 0.01);HCG, weeks 6–8 (P < 0.05); oestradiol, weeks 5–8(P < 0.05) and progesterone, weeks 6–8 (P < 0.05),were lower in anembryonic pregnancies than in those of pregnancieswhich spontaneously aborted. These differences may be a reflectionof the fact that miscarriage, after the demonstration of fetalheart activity, represents fetal demise at a later stage inpregnancy. In anembryonic pregnancies, significant associationswere found between HCG and both oestradiol and progesteronelevels from weeks 6 and 8, suggesting that in the absence ofan embryo, HCG is the prime determinant of steroid synthesisby the corpus luteum.