Gestational Weight Gain and Adverse Outcomes in 1.6 Million Women

Key Takeaways

• Gestational weight gain was evaluated in relation to adverse maternal and neonatal outcomes in a systematic review and meta-analysis of 40 observational studies including 1,608,711 pregnancies.
• Gestational weight gain below recommendations was associated with lower birth weight and higher risks of preterm birth, small for gestational age, low birth weight, and respiratory distress. Gestational weight gain above recommendations was associated with higher birth weight and higher risks of caesarean delivery, hypertensive disorders of pregnancy, large for gestational age, macrosomia, and NICU admission.
• The findings describe associations rather than causation and may help inform updated WHO global gestational weight gain standards.

Rather than testing an intervention or assigning exposures, the analysis synthesized observational evidence on weight gain during pregnancy and outcomes affecting mothers and newborns. The report focuses on observed associations across maternal and neonatal outcomes.

The BMJ article synthesized observational studies from contemporary populations across diverse world regions and income settings. Researchers examined gestational weight gain as the exposure of interest and adverse maternal and neonatal outcomes as the outcome framework. Outcomes included birth weight, caesarean delivery, hypertensive disorders of pregnancy, preterm birth, small or large for gestational age infant, low birth weight, macrosomia, NICU admission, respiratory distress, hyperbilirubinaemia, and gestational diabetes.

Gestational weight gain below Institute of Medicine recommendations was associated with lower birth weight and lower risk of caesarean delivery, large for gestational age infant, and macrosomia. It was also associated with higher risk of preterm birth, small for gestational age infant, low birth weight, and respiratory distress.

Gestational weight gain above recommendations was associated with higher birth weight and higher risk of caesarean delivery, hypertensive disorders of pregnancy, large for gestational age infant, macrosomia, and NICU admission. It was associated with lower risk of preterm birth and small for gestational age infant.

The source context remains observational, so the findings should not be interpreted as establishing causation. The review was designed to inform updated, globally relevant gestational weight gain standards, including the WHO initiative to optimise gestational weight gain guidance for improved perinatal outcomes across world regions.