Physical Partner Abuse During Pregnancy: A Risk Factor for Low Birth Weight in Nicaragua Eliette Valladares, MD, MPH, Mary Ellsberg, PhD, Rodolfo Pen ˜ a, MD, PhD, Ulf Ho ¨ gberg, MD, PhD, and Lars Åke Persson, MD, PhD OBJECTIVE: To assess whether being physically abused dur- ing pregnancy increases the risk of a low birth weight (LBW) infant. METHODS: We conducted a hospital-based case-control study in Leo ´ n, Nicaragua. Cases consisted of 101 newborns with a birth weight under 2500 g, and for each case two controls with a birth weight over 2500 g were selected randomly from infants born the same day. Anthropometry of newborns was done immediately after birth, and back- ground information and data on experiences of violence and potential confounders were obtained through private interviews with mothers. Crude and adjusted odds ratios (ORs) and population-attributable proportion were calcu- lated for exposure to partner abuse in relation to LBW. Multivariate logistic regression analysis was used to control for potential confounding. RESULTS: Seventy-five percent of LBW newborns (cases) were small for gestational age and 40% were preterm. Twenty-two percent of the mothers of LBW infants had experienced physical abuse during pregnancy by their in- timate partners compared with 5% of controls. Low birth weight was associated with physical partner abuse even after adjustment for age, parity, smoking, and socioeco- nomic status (OR 3.9; 95% confidence interval 1.7, 9.3). Given a causal interpretation of the association, about 16% of the LBW in the infant population could be attributed to physical abuse by a partner in pregnancy. CONCLUSION: Physical abuse by a partner during preg- nancy is an independent risk factor for LBW. (Obstet Gynecol 2002;100:700 –5. © 2002 by The American Col- lege of Obstetricians and Gynecologists.) Violence against women by male partners is recognized as one of the most common forms of gender-based violence and is a significant public health concern. 1 In- ternational studies suggested that 1–25% of pregnant women are exposed to physical violence by intimate partners during pregnancy. 2–5 Physical abuse during pregnancy is a potential health hazard both for the woman and the fetus. 6 Women who experience violence during pregnancy are significantly more likely to have conditions such as sexually transmit- ted infections 7,8 ; bleeding 9 –11 ; depression and anxiety 8 ; inadequate prenatal care 11 ; smoking, alcohol, or drug consumption 8,10 ; unintended pregnancy; and poor weight gain. 6,11,12 Most of these conditions are also associated with intrauterine growth restriction and low birth weight (LBW). Research regarding a possible inde- pendent t effect of partner abuse on birth weight has been inconclusive. Although some studies have found that abuse during pregnancy increases the risk of LBW, 9,11,13–15 other studies did not find a significant association. 16,17 This discrepancy might be due to differ- ences in study populations (eg, relative importance of growth restriction among newborns with a low weight and the presence of other contributing factors to LBW), sample size, study design, measurements of violence, analytic approaches, and handling of potentially con- founding variables. 18 The mechanisms linking violence with LBW could be direct, through abdominal trauma linked to placental damage, premature rupture of membranes, 19 or release of prostaglandin leading to preterm labor and LBW. 20 Stress could also constitute an intermediate pathway from violence to LBW, acting through the neuroendo- crine axis, causing the release of catecholamines, beta- endorphin, and cortisol, which can lead to vasoconstric- tion, fetal hypoxia, fetal growth restriction, 21,22 as well as provoke the release of prostaglandin, thereby contribut- ing to preterm labor. 21,23 These potential pathways indi- cate the possibility of multiple mechanisms and multiple From Epidemiology, Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden; Department of Obstetrics and Gynecology, Leo ´n University Hospital, Leo ´n, Nicaragua; Department of Preventive Medicine, National Autonomous University, Leo ´n, Nicaragua; Obstetrics and Gynecology, Department of Clinical Sciences, Umeå University, Umeå, Sweden; Public Health Sciences Division, ICDDR,B: Centre for Health and Population Research, Dhaka, Bangladesh; and Program for Appropriate Technology in Health (PATH), Washington, DC. Funding for this research was provided by SAREC (Swedish Agency for Research Cooperation with Developing Countries). 700 VOL. 100, NO. 4, OCTOBER 2002 0029-7844/02/$22.00 © 2002 by The American College of Obstetricians and Gynecologists. Published by Elsevier Science Inc. PII S0029-7844(02)02093-8