Global Study Reveals Two-Thirds of Pregnancies Experience Unhealthy Weight Gain, Raising Risks for Mothers and Babies
A new systematic review of 1.6 million women’s health data reveals that approximately two-thirds of pregnancies involve gestational weight gain (GWG) falling outside recommended guidelines, significantly increasing the risk of complications for both mother and child. Published by The BMJ, the research underscores the urgent need for updated, globally representative standards for healthy weight gain during pregnancy.
The study, conducted by researchers at Monash University, highlights a growing global challenge. Each year, an estimated 130 million births occur worldwide amidst evolving dietary habits and environmental factors contributing to an “epidemic of excessive GWG.”
“These findings reinforce the need for international reference standards for healthy GWG, as well as lifestyle support and public health measures to improve outcomes for mothers and babies around the world,” stated a lead researcher involved in the study.
Currently, many countries rely on guidelines established by the Institute of Medicine in the 1980s. However, these recommendations are largely based on data from white women in high-income nations and fail to account for the diverse populations and changing conditions present globally. The World Health Organization (WHO) has already initiated efforts to develop more inclusive global standards, and this research provides crucial data to support that initiative.
Researchers analyzed data from 40 observational studies – 36 of which were deemed high quality – spanning 2009 to 2024 and encompassing women from five of the six WHO-defined regions. The analysis revealed a concerning trend: only about one-third (32%) of participants experienced GWG within the recommended ranges. Approximately 23% gained too little weight, while 45% gained too much.
The study demonstrated a complex relationship between GWG and pregnancy outcomes. A GWG below recommended levels was linked to a lower risk of cesarean delivery, large-for-gestational-age infants, and high birth weight, but also correlated with a higher risk of premature birth, small-for-gestational-age babies, and respiratory distress.
Conversely, exceeding recommended GWG levels was associated with increased birth weight, a higher risk of cesarean delivery, hypertensive disorders of pregnancy, large-for-gestational-age infants requiring admission to a neonatal intensive care unit, and a lower risk of premature birth and small-for-gestational-age infants. These trends remained consistent even when applying Asian BMI categories in studies conducted within that region.
Researchers acknowledged certain limitations, including variations in how BMI and GWG are classified across studies and a relative lack of data from low-income countries, which limits the diversity of the findings. They also noted the potential influence of unmeasured factors like smoking, age, and ethnicity.
Despite these limitations, Professor Helena Teede, director of the Monash Center for Health Research and Implementation and an endocrinologist at Monash Health, emphasized the need for a comprehensive approach. “Our findings illuminate and support the need for optimized, evidence-based WHO GWG international reference standards, based on individual patient data, applicable to contemporary and diverse global populations,” she said.
The research underscores that effective guidance on healthy GWG must be integrated into individualized care, prioritizing the reduction of stigma and the optimization of outcomes for both women and their children. Ultimately, the significant health impacts revealed by this study demand concerted action through policy changes, improved healthcare access, and tailored support for maternal and infant health worldwide.
