Most women do not gain the recommended amount of weight during pregnancy, according to a large global analysis that found both lower and higher weight gain are linked to different pregnancy risks. The review looked at outcomes across 40 studies and found that gaining outside recommended ranges is far more common than many people realize.
The findings come from a Monash University-led systematic review published in The BMJ. The analysis included data from 1.6 million pregnancies across five world regions.
Gestational weight gain, or GWG, reflects both maternal changes and a baby’s growth. Too little weight gain has been linked to preterm birth, low birth weight and infants who are small for gestational age. Gaining more than recommended can raise the chances of hypertensive disorders, caesarean delivery, a larger infant size and the need for neonatal intensive care.
First author Dr. Rebecca Goldstein said the results highlight the need for clearer, more global guidance.
“These findings reinforce the need for international reference standards for healthy GWG alongside lifestyle support and public health measures to improve outcomes for mothers and babies worldwide,” she said.
Across all studies, only 32% of women gained weight within recommended ranges. Another 23% gained below the range, while 45% gained above it. Many countries still rely on weight gain recommendations created more than three decades ago from a limited population that does not reflect the diversity of today’s pregnancies.
The World Health Organization is working on new international standards. The authors say the updated guidelines should reflect modern food environments, broader BMI ranges and different population needs. Similar patterns were seen in studies using Asian BMI categories.
The review notes limitations, including inconsistent definitions across studies and fewer data from low income regions. Other factors like maternal age, smoking status and ethnicity were not consistently reported and may affect outcomes.
Senior author Professor Helena Teede said global standards need to support real-world needs.
“Our findings inform and support the need for optimized, evidence-based WHO international GWG reference standards based on individual patient data, applicable to contemporary and diverse global populations,” she said. She added that recommendations must be personalized. “Ultimately, the burden of health impacts shown here mandate action to support women across policy, health care and individual level solutions for the health of mothers and babies.”
For readers, the takeaway is that weight gain during pregnancy varies widely and depends on factors like access to prenatal care, food availability, pre-pregnancy health and other daily realities. Updated, individualized guidance may help reduce confusion and improve support for families during pregnancy.
This research was supported by fellowships from the National Health and Medical Research Council of Australia, the Heart Foundation and Veski.