ABSTRACT
This study aimed to investigate the association between pre-pregnancy maternal body mass index [BMI], gestational weight gain and low birth weight [LBW] in babies born to a sample population of Omani women. A case-control study was carried out among deliveries registered between 1[st] May 2010 and 30[th] April 2011 at Sultan Qaboos University Hospital, Muscat, Oman. A case was defined as a woman who delivered a low birth weight baby [<2,500 g]; a control was a woman delivering a baby weighing between 2,500 and 4,000 g. A random selection of 150 cases and 300 controls was carried out using the hospital information system. Maternal, pre-natal, and delivery data were extracted from the mothers' follow-up cards. Bivariate and multivariate logistic regression analyses were executed to examine the association between pre-pregnancy maternal BMI and LBW. The percentage of underweight mothers [BMI <18.5] was higher among the cases compared to the controls [17.3% versus 6%; P <0.001]. The proportion of mothers with less-than-recommended weight gain was also higher among the cases compared to the controls [57.7% versus 33%; P <0.001]. After adjustment for potential confounders, infants of underweight mothers had more than twice the risk of LBW compared to those of mothers with normal weight [odds ratio = 2.27; 95% confidence interval 1.09-4.71]. Underweight Omani women as well as women with less-than-recommended gestational weight gain were at higher risk of delivering LBW babies. Maternal health promotion programmes should be directed towards improving mothers' nutrition before and during pregnancies