To assess intimate partner violence (IPV) in a longitudinal cohort study during and after pregnancy, and examine social and economic factors encouraging or inhibiting violence. Nulliparous women were recruited from 6 public hospitals in Melbourne, Australia. Self-administered questionnaires included standardised measures assessing fear of an intimate partner at enrolment, 6 and 12 months postpartum; and period prevalence of physical and emotional abuse in the first 12 months postpartum. 1,507 women completed baseline data (mean gestation 15 weeks). Response fractions at 3, 6 and 12 months postpartum were 95, 93 and 90%, respectively. 5.1 and 5.4% of women reported fear in pregnancy and the first year postpartum, respectively. 17% experienced physical and/or emotional abuse in the first year postpartum. Most women who reported fear of an intimate partner in the first year after the index birth reported fear before and/or during pregnancy. Women working in early pregnancy who qualified for paid maternity leave had significantly reduced odds of reporting combined physical and emotional IPV in the first 12 months postpartum compared with women not working (Adj. OR 0.21, 95% CI 0.08-0.55). Women working but not eligible for paid leave had reduced odds compared with women not working (Adj. OR 0.49, 95% CI 0.24-1.00). Models adjusted for maternal age, relationship status, income and education level. Few first time mothers reported fear for the first time after childbirth suggesting that IPV more commonly commences prior to the first birth. Paid maternity leave may have broader social benefits beyond immediate financial benefits to women and families.