ABSTRACT
Objective To explore the impact of hepatitis B virus infection, intrahepatic cholestasis during pregnancy on the risk of small for gestational age (SGA) and low birth weight (LBW), and analyze the interaction effect. Methods The study was conducted from Jan 2017 to Apr 2018 at the Gansu Provincial Maternity and Child Care Hospital in Lanzhou, China. The peripheral blood hepatitis B surface antigen (HBsAg) and total bile acids of pregnant women were determined by chemiluminescence method, unconditional Logistic regression models were used to estimate association between hepatitis B virus infection, intrahepatic cholestasis of pregnancy and the risk of neonate outcomes. Results After adjusting for confounding factors, compared to normal pregnant women, HBV infection alone or ICP alone during pregnancy did not increase the risk of SGA or LBW. The increased risk of born before term SGA (OR=1.76, 95% CI:1.16-2.65, P=0.007) and LBW infants (OR=1.85, 95%CI:1.44-2.38, P<0.001) were observed in pregnant women with HBV infection and ICP, the additive and multiplicative interaction were also observed for before term SGA ［RERI (95% CI) =6.54(0.14-12.94), AP (95% CI) =0.90%(0.68%-1.13%), S (95% CI)=7.03(1.38-42.64)］ and LBW ［RERI (95% CI) =5.69(0.48-10.90), AP (95% CI) =0.76%(0.55%-0.97%), S (95% CI)=8.02(1.92-33.43)］. Conclusions Our results suggest that pregnancy HBV infection combined with ICP increase the risk of SGA and LBW infants. These two risk factors had a synergistic effect.