Relationship between increased maternal serum free human chorionic gonadotropin levels in the second trimester and adverse pregnancy outcomes: a retrospective cohort study

Abstract

Background A retrospective cohort study was conducted to collect the data of pregnant women who received hospital delivery in Hangzhou Women's Hospital from January 2018 to December 2020, and who participated in the second trimester (15–20+6 weeks) of free beta human chorionic gonadotropin (free β-hCG). And the study was conducted to explore the relationship between maternal serum free β-hCG and adverse pregnancy outcomes (APO). Methods We retrospectively analyzed the clinical data of 1,978 women in the elevated maternal serum free β-hCG group (free β-hCG ≥ 2.50 multiples of the median, MoM) and 20,767 women in the normal group (0.25 MoM ≤ free β-hCG < 2.50 MoM) from a total of 22,745 singleton pregnancies, and modified Poisson regression analysis was used to calculate risk ratios (RRs) and 95% confidence intervals (CI) of the two groups. Results The gravidity and parity in the elevated free β-hCG group were lower, and the differences between the groups were statistically significant (all, P < 0.05). The risks of polyhydramnios, preeclampsia, and hyperlipidemia, were increased in women with elevated free β-hCG levels (RRs: 1.996, 95% CI: 1.322–3.014; 1.469, 95% CI: 1.130–1.911 and 1.257, 95% CI: 1.029–1.535, respectively, all P < 0.05), intrauterine growth restriction (IUGR) and female infants were also likely to happen (RRs = 1.641, 95% CI: 1.103–2.443 and 1.101, 95% CI: 1.011–1.198, both P < 0.05). Additionally, there was an association between elevated AFP and free β-hCG levels in second-trimester (RR = 1.211, 95% CI: 1.121–1.307, P < 0.001). Conclusions APOs, such as polyhydramnios, preeclampsia, and hyperlipidemia, were increased risks of elevated free β-hCG levels, IUGR and female infants were also likely to happen. Furthermore, there was an association between elevated AFP levels and elevated free β-hCG levels in second-trimester. We recommend prenatal monitoring according to the elevated maternal serum free β-hCG level and the occurrence of APO.