The association between unexplained second-trimester maternal serum hCG elevation and pregnancy complications.

Abstract

We conducted this cohort analytic study to determine whether women with unexplained elevations of maternal serum hCG at 16-20 weeks' gestation are at increased risk for pregnancy complications and adverse perinatal outcomes. The inclusion criteria were a singleton gestation, a confirmed gestational age, and an hCG level greater than 2.5 multiples of the median (MOM). The exclusion criteria were fetal anomalies, an abnormal karyotype, and a maternal serum alpha-fetoprotein (MSAFP) level greater than 2.5 MOM. A group of randomly selected women with normal hCG and MSAFP levels served as controls. Of the 6011 women screened, 284 (4.7%) had an unexplained elevated hCG level. Patients with elevated levels of hCG had a significantly higher risk for hypertension (odds ratio 4.4; 95% confidence interval [CI] 1.9-10) and fetal growth restriction (odds ratio 2.8; 95% CI 1-7). Women with hCG levels greater than 4 MOM also had an increased risk of preterm delivery (odds ratio 3.3; 95% CI 1.3-8.2). Pregnancies with unexplained elevated hCG levels should be regarded as high-risk pregnancies and managed accordingly.