Human Chorionic Gonadotrophin Levels Between 15 and 17 Weeks in Women who Subsequently Develop Preeclampsia

Abstract

Objectives: Preeclampsia (PET) is associated with abnormal cyto-trophoblast invasion. Serum levels of human chorionic gonadotrophin (hCG) reflect both the volume and maturity of trophoblast. Our aim was to investigate whether early midtrimester levels of maternal serum hCG in women subsequently developing preeclampsia differ from those of the normal pregnant population.Method: A retrospective analysis of serum βhCG concentrations measured, between 15 and 17 weeks, as part of antenatal serum screening for fetal Down's syndrome in women who subsequently developed PET. The βhCG concentrations were expressed as multiples of the median value for the local population adjusted for gestational age. The women had otherwise uncomplicated singleton pregnancies and delivered chromosomally normal fetuses. A sample from the original population was taken as a control group (n = 625).Results: Forty-eight women who developed PET were identified. Their second trimester βhCG was significantly elevated (P = 0.0008) with a median of 1.30 MOM when compared to that of the control group MOM. The mean gestational age at delivery was 35 weeks, 4 days and the population's mean birthweight was on the 40th centile. There was no difference in the α-feto-protein levels.Conclusions: This study shows that women who subsequently develop preeclampsia tend to have elevated serum hCG levels early in the second trimester compared to the population as a whole. This may be associated with abnormal early placental development, such as hyperplacentosis or delayed placental maturation.