Placental hCG immunohistochemistry and serum free-Beta-hCG at 11–13 weeks’ gestation in intrauterine fetal demise

Abstract

Intrauterine fetal demise (IUFD) is a continuing problem that can result in severe psychosocial trauma for expecting parents. Our aim was to analyze placental human chorionic gonadotropin (hCG) expression at the third trimester and free-Beta-hCG levels measured at 11-13 weeks in cases of IUFD that occurred after 34 weeks' gestation, alongside a parallel analysis of a set of controls. In this retrospective study we present immunohistochemical data of a tissue microarray that included the following: 12 placentas where IUFD occurred (24 samples); 28 control placentas from first and early second trimester (56 samples); and 30 control placentas at term of pregnancy (60 samples). We used immunohistochemistry to analyze the expression of hCG. Data are also presented from 3,240 first trimester trisomies screening tests, of which 21 pregnancies resulted in IUFD (15 after 22 weeks' gestation and 6 after 34 weeks). All pregnancies took place between 2001 and 2010. For each case, our analysis took account of pregnancy-related data that we gathered from the relevant clinical files. Small for gestational age (SGA) was defined as neonatal weight <10th centile. Our results show that full-term placentas displayed a decreased immunohistochemical expression of hCG in comparison with those at the first trimester (p < 0.05). Moreover, low hCG expression in placentas at the third trimester was shown to be an independent risk factor for IUFD after 34 weeks' gestation (under multivariate analysis with p < 0.05). When we reviewed first trimester screening results, free-Beta-HCG was found to be lower for the group of IUFD after 34 weeks' gestation than in the group of live births (p < 0.05). This difference was heavily weighted by non small for gestational age (non-SGA) associated cases of IUFD: these presented a free-Beta-hCG MoM log of -0.27 (± 0.09) in contrast to just -0.01 (± 0.03) in SGA-associated IUFD (p < 0.05). Our results show that low hCG is an independent risk factor for IUFD after 34 weeks' gestation, and that levels of the hormone are significantly lower in non-SGA associated cases of IUFD.