Different methods for assessing gestational weight gain and its association with birth weight

To analyze association of different methods of gestational weight gain assessment with live births small for gestational age (SGA) and large for gestational age (LGA).

This was a cross-sectional study with adult women, normal prepregnancy BMI, single pregnancy and gestational age at delivery ≥28 weeks, from the "Birth in Brazil" study, between 2011 and 2012.

Among the 11,000 women participating in the study, prevalence of excessive weight gain was 33.1% according to the Brandão et al. and Institute of Medicine (IOM) methods, and 37.9% according to the Intergrowth method. The chance of being born SGA in the case of insufficient weight gain was OR=1.52 (95%CI 1.06;2.19), OR=1.52 (95%CI 1.05;2.20) and OR=1.56 (95%CI 1.06;2.30) for the Brandão et al., IOM and Intergrowth methods, respectively. Likelihood of excessive weight gain using the same methods was OR=1.53 (95%CI 1.28;1.82), OR=1.57 (95%CI 1.31;1.87) and OR=1.65 (95%CI 1.40;1.96), for LGA respectively.

Compared to the IOM recommendations, the Intergrowth and Brandão et al. methods show themselves to be alternatives for identifying SGA and LGA.