Association of intimate partner violence during pregnancy and birth weight among term births: a cross-sectional study in Kaduna, Northwestern Nigeria.

Objective: To determine the association of prenatal exposure to intimate partner violence (IPV) with birth weight as a continuous variable among term births in a Nigerian population.

Design: Cross-sectional study.

Setting: Mother-child pairs recruited when their newborns were brought for BCG or other vaccines shortly after birth at the Child Welfare Clinic of Barau Dikko Teaching Hospital, Kaduna, Nigeria.

Participants: 293 women with term birth infants.

Main Exposure And Outcome Measures: Emotional, physical and sexual IPV were measured postnatally by interview using the Conflict Tactics Scale. Birth weight in grams was the main outcome measure. Linear regression, with adjustment for covariates, was used to estimate associations between birth weight and exposure to the presence, and frequency, of IPV.

Results: Sixty-seven per cent of mothers experienced at least one of the three forms of IPV during pregnancy. Relative to the 33% of women with no prenatal exposure to any form of IPV, we observed a reduction in birth weight of 94 g (95% CI: -202 to 15) for prenatal exposure to emotional IPV, 162 g (95% CI -267 to -58) for physical IPV and 139 g (95% CI -248 to -30) for sexual IPV. The combination of all three forms of IPV was associated with a 223 g reduction in birth weight (95% CI -368 to -77). Increasing occurrences of each of the three types of IPV were associated with greater reductions in birth weight. For physical IPV, relative to no exposure to any form of IPV, birth weight was lower by 112 g (95% CI -219 to -4) with 1-5 instances and 380 g (95% CI -553 to -206) for >5 instances over the pregnancy.

Conclusions: Maternal exposure to IPV was associated with shifting of the birth weight distribution among term newborns. A dose-response relationship was observed between frequency of IPV and birth weight.