Low birth weight at term: relationship with maternal anthropometry

The objective of this study was to determine the relationship of maternal anthropometry with low birth weight at term. This study was conducted at the Maternity Hospital, Thapathali, from 6th December 2004 to 30th January 2005. It was a prospective, hospital based, comparative study, carried out in 308 women who had delivered singleton live babies at term. The study population was divided into two groups based on baby's weight. During the study period, 154 women, who had delivered term low birth weight (LBW) babies (<2500gm), were taken as cases. For each case, a comparative case (matching in age and parity) who had delivered normal birth weight (NBW) baby (2500gm) was selected and served as control. Maternal anthropometric measurements were compared between the two groups. The variables studied were post-delivery maternal weight, height, body mass index (BMI) and mid upper arm circumference (MUAC). The incidence of low birth weight during the study period was 12.76% (329 of 2577 total births). The incidence of term low birth weight was 8.15% among the 2283 term births. In mothers with low weight (<45.0kg), low birth weight babies were three times more common than in mothers with normal weight (OR 3.5 95% CI 1.82-6.77) and with low MUAC (<22.0cm), it was twice as common (OR 2.04 95% CI 1.14-3.63). In mothers with low height (<145.0cm), LBW babies were higher but could not reach significant level (OR 1.87 95% CI 0.98-3.75). Similarly, in mothers with low BMI (<18.5kg/m2), the difference was not significant (OR 1.9 95%CI 0.61-5.65). On multiple logistic regression analysis, only low maternal weight was powerful enough to remain significant (OR 2.84 95% CI 1.34-5.99). From these results, it can be concluded that low maternal anthropometric measurements have a definite role in causing LBW babies at term. Among the studied variables, maternal weight showed the strongest influence on low birth weight.