A major new study has revealed that a significant majority of women are not gaining the recommended amount of weight during their pregnancies, a situation that poses serious health risks for both the mother and child.
Widespread Issue with Pregnancy Weight
Researchers from Monash University in Australia led an international analysis of data from over 1.6 million women. Their findings, published in The BMJ on Wednesday 19 November 2025, show that only a third of pregnant women (32%) gained weight within the recommended guidelines.
The study found that 45% of women gained more weight than advised, while a further 23% did not gain enough. This means a total of two-thirds of pregnant women experienced gestational weight gain (GWG) outside the healthy range.
Pre-Pregnancy Health and Weight Patterns
The research also shed light on women's health before conception. Only just over half of the women studied (53%) had a body mass index (BMI) within the 'normal' range before becoming pregnant.
Before pregnancy, 19% of women were overweight, 22% were obese, and 6% were underweight. This pre-existing weight status can influence both the pregnancy weight gain and the associated health outcomes.
Serious Consequences for Mother and Baby
The analysis provides a clear picture of the risks associated with inappropriate weight gain during pregnancy. When mothers gain more weight than recommended, their babies face a higher risk of being born with a large birth weight and are more likely to require admission to a neonatal intensive care unit.
Mothers who gain excess weight face an elevated risk of caesarean delivery and high blood pressure during pregnancy.
Conversely, when mothers do not gain enough weight, their babies are at increased risk of being born prematurely, having a low birth weight, or being small for their gestational age. The study also identified that these babies have a higher risk of respiratory distress syndrome.
This research is the first meta-analysis to highlight the increased risk of NICU admissions associated with excessive weight gain and the connection between insufficient weight gain and respiratory problems in newborns.
Call for Greater Awareness and Support
The study authors emphasised that various factors contribute to weight issues before and during pregnancy, including what they term 'eco-social vulnerabilities'. These encompass ultra-processed food consumption, living environment, and socioeconomic status.
The researchers concluded that their findings 'definitively reinforce the need for recognition of the risks' associated with gestational weight gain outside the Institute of Medicine recommendations, calling for increased support and education for expectant mothers.
