According to a new study published in The BMJ, around 68% of pregnant women gain either too much or too little weight compared to current recommendations. A worrying trend, associated with increased risks of complications such as prematurity, abnormally high birth weight or even a passage in neonatal intensive care.
Obsolete and unrepresentative directives
For the lead authors, Helene Teede and Rebecca Godstein, these results send a strong signal: “It becomes essential to establish international standards for healthy gestational weight gain, accompanied by robust public health measures.”
Indeed, most countries still rely on recommendations dating back to the 1980s and based mainly on data from white women living in rich countries. They do not reflect global ethnic diversity, changing eating habits, or the overall increase in BMI.
To fill this gap, the World Health Organization (WHO) has launched an initiative to develop new global standards.
A global analysis of five regions of the world
To support this work, the researchers screened 40 observational studies conducted between 2009 and 2024. In total, 1.6 million women from five of the six regions defined by the WHO were included.
Before their pregnancy, 53% had a normal BMI, while the remainder were classified as underweight (6%), overweight (19%) or obese (22%). Only 32% gained weight within recommended ranges; 23% took too little, 45% too much or too much.
A data which is not trivial. Insufficient weight gain reduced certain risks (such as that of cesarean section or macrosomia – babies weighing more than 4 kilos), but increased those of prematurity, low birth weight and respiratory distress.
Conversely, excessive weight gain increased the risks of hypertension, macrosomia, cesarean delivery, or admission to intensive care, while decreasing the risk of prematurity.
Limits, but a clear message
Researchers recognize several limitations: variations in classification according to region, lack of studies in low-income countries, or even absence of certain data such as smoking or maternal age. Despite this, their conclusion remains firm:
“Our findings support the need for optimized, evidence-based international standards applicable to contemporary and diverse populations.”
Towards a more nuanced approach in the future?
In an associated editorial, specialists Annick Bogaerts and Dominika Osicka highlight the most striking element: the variations according to BMI and regions, which call into question an overly rigid approach.
According to them, “rather than a uniform warning against exceeding fixed thresholds, a more nuanced approach is needed, focused on weight gain patterns, their determinants and personalized, non-punitive support.”
They also call for strong political action: “Without comprehensive lifelong public health strategies, the obesity epidemic will continue from generation to generation.” And to conclude: “Governments must act without delay to support women’s health before, during and after pregnancy.”