Introduction:
Intimate partner violence (IPV) is a public health problem that affects millions of women worldwide. The role of violence as an underlying factor in poor birth outcomes remains an area where strong evidence is lacking. The aim of this study was to determine the association between intimate partner violence (IPV) and preterm delivery (PTB) and low birth weight (LBW).

Materials and methods:
A prospective cohort study was conducted among 1112 pregnant women attending antenatal care in Moshi–Tanzania. The women were enrolled before 24 weeks gestation, followed-up at week 34 to determine exposure to violence during pregnancy, and after delivery to estimate gestation age at delivery and birth weight. Logistic regression analysis was performed to assess the association between exposure to IPV during pregnancy and PTB and LBW while adjusting for possible confounders. In addition, stratified analysis based on previous history of adverse pregnancy outcome was performed.

Results:
One-third of the women experienced IPV during pregnancy, 22.3% reported emotional, 15.4% sexual and 6.3% physical violence. Women exposed to physical IPV were three times more likely to experience PTB (AOR = 2.9; CI 95%: 1.3–6.5) and LBW (AOR = 3.2; CI 95%: 1.3–7.7). Women with previous adverse pregnancy outcomes and exposure to physical IPV had a further increased risk of PTB (AOR = 4.5; CI 95%: 1.5–13.7) and LBW (AOR = 4.8; CI 95%: 1.6–14.8) compared to those without previous history of adverse outcome.

Conclusion:
Women who are exposed to IPV during pregnancy are at increased risk of PTB and LBW. The risk is even stronger if the women additionally have suffered a previous adverse pregnancy outcome. Interventions addressing IPV are urgently needed to prevent occurrence and reoccurrence of PTB and LBW.