The impact of gestational diabetes mellitus on pregnancy outcomes in women with hepatitis B virus: a retrospective cohort study

To investigate the impact of hepatitis B virus carriers combined with gestational diabetes mellitus (HBVC & GDM) on pregnancy outcomes in a cohort of pregnant women from Hangzhou, China. We set-up a retrospective cohort study to analyze data from 12,815 pregnant women who delivered in three Hangzhou tertiary hospitals between 2015 and 2022. Four groups were created according to the presence of HBV and/or GDM as follows: a non-HBVC & GDM group (n = 5,323), a HBVC group (n = 5,508), a GDM group (n = 919) and a HBVC & GDM group (n = 1,065). Univariate analysis was carried out with the Mann-Whitney U test or the chi-squared test; P < 0.05 was used as the screening criterion. Multivariate logistic regression analysis was then performed to investigate the effects of each of the relevant confounders on HBVC, GDM and HBVC & GDM. After adjusting for potential confounding variables, the results were expressed as odds ratios (ORs) and 95% confidence intervals (95% CIs), with P < 0.05 considered as statistically significant. The incidence of HBVC & GDM among pregnant women in Hangzhou, China was 0.96% (95% CI: 0.90-1.02%). The median maternal age of the pregnant women in the HBVC & GDM group was significantly higher than that in the HBVC, GDM and control groups (31.00 vs. 30.00, 30.00, 29.00, P < 0.001). The proportions of low birth weight (4.0% vs. 3.8%, 3.4%, 3.4%) and macrosomia (6.8% vs. 5.4%, 3.7%, 4.3%) in the HBVC & GDM group were significantly higher than in the other three groups, with significant differences between groups (P < 0.05). Multivariate logistic analysis revealed a progressive increase in risk values with increasing maternal age in the HBVC & GDM group (OR≥ 25&<30=1.632, OR≥ 30&<35=3.257, and OR≥ 35=5.611). In addition, the carriage risk of pregnant women over 35 years was approximately two-fold higher than that in the HBVC and GDM groups (5.611/2.251 and 5.611/3.130), respectively. The risk value increased progressively with increasing gravidity (OR2 = 1.364 and OR≥ 3=1.765). The risk of a floating population was as follows: Zhejiang-registered but non-Hangzhou (OR = 2.246) > outside Zhejiang Province (OR = 1.953) > Hangzhou-local (OR = 1). HBVC & GDM also increased the risk of intrahepatic cholestasis of pregnancy (ICP) (OR = 3.143, 95% CI: 2.223-4.445), pre-eclampsia (PE) (OR = 2.017, 95%CI: 1.315-3.095), macrosomia (OR = 1.548, 95% CI: 1.161-2.064), assisted vaginal delivery (OR = 1.501, 95% CI: 1.185-1.901) and Caesarean section (OR = 1.258, 95% CI: 1.035-1.528). HBVC & GDM also reduced the chance of delayed labor (gestational age > 41 week, OR = 0.217, 95% CI: 0.126-0.374). The incidence rates of HBVC and GDM among pregnant women in Hangzhou City are relatively high. When HBVC & GDM co-existed, the risks of ICP, PE and macrosomia increased significantly. The risk of HBVC & GDM tended to increase progressively with increasing maternal age and increasing gravidity. For pregnant women of advanced age, those with increasing gravidity or those in a floating population, it is important to enhance educational awareness related to HBV, GDM, and especially HBVC & GDM in order to provide personalized antenatal medical care and reduce the risk of adverse pregnancy outcomes.