Gestational weight gain and the risk of infant mortality amongst women with normal prepregnancy BMI: the Friedmann-Balayla model.

OBJECTIVE: The study of the association between gestational weight gain (GWG) and infant mortality is riddled with methodological concerns, particularly with limitations in accounting for gestational age-specific weight gain. In our study, we developed a new model, which accounts for gestational age, to determine whether insufficient or excessive GWG is associated with an increased risk of infant death amongst women with normal prepregnancy BMI (18.5-24.9 kg/m2 ).

METHODS: We developed and implemented the Friedmann-Balayla model to mitigate gestational age-related biases in our assessment, and conducted a population-based cohort study using the CDC's 2013 Period-Linked Birth-Infant Death data. The impact of GWG according to the 2009 IOM guidelines on the risk of infant mortality was estimated using logistic regression analysis, adjusting for relevant confounders.

RESULTS: Our cohort consisted of 1,517,525 singleton deliveries and 6138 infant deaths. Overall, relative to women achieving adequate GWG, neither women gaining insufficient nor excessive weight had greater odds of infant death during the first year of life (OR [95%CI]): 1.06 [0.97-1.17] (p = 0.174), and 0.98 [0.91-1.04] (p = 0.523), respectively. This relationship did not change when restricting our analysis to term or preterm deliveries or when conducting sensitivity analyses accounting for maternal morbidities (p > 0.05).

CONCLUSION: Using this novel analytic approach, there does not appear to be an increased risk of infant mortality if GWG falls outside of the IOM guidelines in women with normal prepregnancy BMI. Future studies should apply this methodology to other BMI categories.