Summary. The aim of this study was to examine the contribution of hepatitis B virus (HBV) and hepatitis C virus (HCV) to pregnancy-related complications including gestational diabetes mellitus (GDM), preterm birth (PTB), intrauterine growth restriction (IUGR), pre-eclampsia, antepartum haemorrhage and cholestasis. The Nationwide Inpatient Sample was queried for all pregnancy-related discharges, pregnancy complications and viral hepatitis from 1995 to 2005. Logistic regression was used to examine the association between HBV, HCV, HBV + HCV and pregnancy-related complications including GDM, PTB, IUGR, pre-eclampsia, antepartum haemorrhage, cholestasis and caesarean delivery. Model covariates included maternal age, race, insurance status, substance use and medical complications including liver complication, hypertension, HIV, anaemia, thrombocytopenia and sexually transmitted infections. Of 297 664 pregnant women data available for analysis, 1446 had a coded diagnosis of HBV, HCV or both. High-risk behaviours, such as smoking, alcohol and substance use were higher in women with either HBV or HCV. Women with HBV had an increased risk for PTB (aOR 1.65, CI [1.3, 2.0]) but a decreased risk for caesarean delivery (aOR 0.686, CI [0.53, 0.88]). Individuals with HCV had an increased risk for GDM (aOR 1.6, CI [1.0, 2.6]). Individuals with both HBV and HCV co-infection had an increased risk for antepartum haemorrhage (aOR 2.82, CI [1.1, 7.2]). There was no association of viral hepatitis with IUGR or pre-eclampsia. Women with hepatitis have an increased risk for complications during pregnancy. Research to determine the efficacy and cost-effectiveness of counselling patients about potential risks for adverse outcomes is warranted.