Although small-scale studies have suggested that being physically abused by an intimate partner around the time of pregnancy is associated with the risk of gaining too little or too much gestational weight, this relationship found little support in analyses of data from the 2000–2006 Oklahoma Pregnancy Risk Assessment Monitoring System (PRAMS).1 Seven percent of women aged 20 and older had experienced intimate partner violence before or during pregnancy. Of these, 39% had had adequate gestational weight gain, 28% had gained too little weight and 33% had gained too much. Positive and significant associations between abuse and gestational weight gain occurred only among women aged 35 and older.
PRAMS, which is conducted by the Centers for Disease Control and Prevention, is an ongoing surveillance project that gathers population-based, state-by-state data on women’s perinatal attitudes and experiences. All PRAMS states collect data on physical abuse, but only Oklahoma collects data on gestational weight gain. Investigators sought to determine whether women who had been physically abused by an intimate partner in the year before or during pregnancy were less likely than nonabused women to gain pregnancy weight within guidelines set by the Institute of Medicine. These guidelines, created to maximize maternal and infant health, suggest weight gains of 12.5–18.0 kg, 11.5–16.0 kg and 7.0–11.5 kg for underweight, normal and obese women, respectively. Researchers classified women as physically abused around the time of pregnancy if they reported having been "physically hurt in any way" by their husband or partner during the year before they got pregnant or during their most recent pregnancy. Women’s self-reported prepregnancy weight was used to assess the adequacy of their total gestational weight gain. Logistic regression analyses controlling for social, demographic, health and lifestyle characteristics examined the relationship between abuse and gestational weight gain.
Eighty-one percent of the women were white, and 69% were married. Their mean age was 27. About one-third had never given birth, and almost half had more than a high school education. Most (86%) had begun prenatal care during their first trimester; 55% had had at least one pregnancy complication, and 46% had had an unintended pregnancy. Some 34% had experienced three or more stressful life events during pregnancy; in their third trimester, 9% had smoked cigarettes, and 2% had drunk alcohol. Five percent reported physical violence before pregnancy, 4% during pregnancy and 7% before or during pregnancy. Weight gain was adequate in 39% of women reporting violence, inadequate in 28% and excessive in 33%.
The odds of being physically abused before or during pregnancy were higher for women aged 20–24 than for those aged 35 or older (odds ratio, 2.2). Black or unmarried women, compared with white or married women, had elevated odds (1.6 and 4.2). Women who had experienced three or more stressful events during pregnancy faced higher odds of abuse than women who had experienced none (27.4). The odds also were increased for women who had experienced any pregnancy complications, smoked or drunk in the last trimester or had a pregnancy that was unintended, compared with those who had not (1.9–3.8). Having more than 12 years of education was associated with reduced odds of physical abuse (0.3).
In univariate analyses, deficient weight gain was not associated with intimate partner violence around the time of pregnancy, but it was associated with demographic characteristics. For example, black, Asian and unmarried women had significantly elevated odds of gaining less gestational weight than the guidelines recommended, compared with white and married women (odds ratios, 1.2–1.9). Odds also were elevated for women who had given birth at least twice, compared with those who had never given birth (1.5–1.6). And they were elevated for women who had sought no prenatal care, compared with those who had sought it during their first trimester (5.4). Women who had drunk alcohol during the last trimester or had an unintended pregnancy had higher odds than those who had not (1.8 and 1.3).
By comparison, a significant crude relationship was found between intimate partner violence and excessive gestational weight gain (odds ratio, 1.5). Women who were younger than 35 had significantly increased odds of gaining too much pregnancy weight, compared with those aged 35 or older (1.2–1.6). Unmarried and overweight women faced higher odds than women who were married or not overweight (1.4 and 2.1). Odds were higher for women who had experienced three or more stressful life events than for those who had experienced none (1.3). They also were higher for women who had had an unintended pregnancy than for those who had not (1.3). However, women who had given birth at least once had lower odds of gaining too much pregnancy weight than women who had never given birth (0.6–0.7).
Neither inadequate nor excessive weight gain was associated with intimate partner violence in analyses adjusting for age, marital status, education, pregnancy intention, stressful life events, smoking and alcohol use during the third trimester, and gestational age at delivery. However, age-stratified analyses revealed associations between physical violence around the time of pregnancy and gaining too little or too much gestational weight among women aged 35 and older (odds ratios, 8.8 and 7.5, respectively).
The researchers note several study limitations. Because the PRAMS data are cross-sectional, a causal relationship between physical violence around the time of pregnancy and significantly excessive weight gain among older women cannot be established. Furthermore, the self-reporting of prepregnancy weight and gestational weight gain may have led to misclassified outcomes and underestimated measures. Also, the study did not assess emotional, sexual or other types of family violence, all of which may have been related to gestational weight gain.
The researchers conclude with a call for more research to see if emotional and sexual abuse are associated with pregnancy weight gain, and whether weight gain may be a pathway through which such abuse affects pregnancy outcomes. They add that understanding the potential role of biological, psychological and social elements in the relationship between interpersonal violence and gestational weight gain may enhance prevention efforts.—A Kott