Doctors have warned that rising obesity rates among pregnant women are endangering both mothers and babies.
Over a quarter of pregnant women in the UK are now classified as obese.
The Royal College of Physicians (RCP) has urged that this be “recognised as an urgent and growing public health challenge”.
Obesity is “contributing to avoidable harm” while also putting increased pressure on NHS maternity services, according to the new report.
The college said there must be “bold, joined-up action” from food policy, education and healthcare to better prevent obesity in general.
The “stigamatisation” of women’s weight also “remains an issue” and should be replaced by non-judgmental care before, during and after pregnancy, experts said.
The body mass index (BMI) of women is taken during early pregnancy. In 2023/24, the proportion of women classed as obese following this measurement was 26.2 per cent.
The RCP warned that this can increase the risk of developing diabetes during pregnancy, as well as pre-eclampsia, which causes persistent high blood pressure.
Having a Caesarean section is more than twice as likely among obese women while haemorrhaging after birth is almost twice as likely, the report said.
The 2021–24 MBRRACE-UK Confidential inquiry into maternal deaths report also showed that 64 per cent of women who died in pregnancy or in the six weeks after giving birth were overweight or obese.
Obesity is “associated with adverse outcomes for both women and children”, the report said, although the approach from healthcare services “lacks coherence and pace”.
Taking action to reduce rates of obesity among pregnant women and those of childbearing age would “substantially” lower demand for complex maternity services, reduce infant death and “improve life chances for thousands of babies”, the RCP added.
Dr Kath McCullough, special adviser on obesity at the RCP, said: “Maternal obesity is one of the clearest signs that we need to tackle the root causes of obesity and weight gain, recognising the benefits not only for pregnancy but also women’s health and future generations.
“We know that obesity is driven by inequality, poverty and environments that make healthy choices harder every day.
“We need bold, joined-up action across the system – from food policy and education to healthcare services, professional training and research to better prevent obesity in the first place and better support women living with obesity in the pre- and postnatal periods.
“Getting this right would transform outcomes for families and deliver lasting benefits for the NHS.”
The RCP report highlights a number of “priority areas” for action, which includes improving pre-pregnancy education to highlight the impact of obesity on reproductive health and transforming the food system to encourage healthier choices.
It also called for the Government to bolster the Healthy Start scheme, which it describes as a “vital nutritional safety net”.
Dr Anita Banerjee, obstetric physician and RCP censor, added: “Too often, women arrive in pregnancy already at risk, having had little support beforehand to address the factors affecting their health.
“By the time they are pregnant, opportunities for preventing obesity and the risks associated with it have already been missed.
“This is why action before, during and after pregnancy matters so much. If we want safer pregnancies and healthier babies, and a healthier society, we need to prioritise women’s health long before they reach a maternity unit. Prevention is better than treatment.”
There are regional variations in obesity rates among pregnant women. Rates were highest in the north east of England (32.3 per cent) and lowest in London (20 per cent), with black women more likely to be obese (36.3 per cent).
The figures mirror obesity trends in general, according to the RCP.
Dr Alison Wright, president of the Royal College of Obstetricians and Gynaecologists (RCOG), added: “Stigmatisation of women and their weight remains an issue, which is exacerbated by health inequalities.
“This must be replaced by the provision of accessible, non-judgmental, evidence-based information support and care, before, during and after pregnancy.
“The RCOG has developed clinical guidance to support clinicians in caring for pregnant women with obesity, which can increase the risk of pregnancy complications, the likelihood of intervention during labour and conditions such as gestational diabetes and pre-eclampsia.
“We must see maternity services appropriately resourced, with the right staffing levels, training and facilities to care for women with increasingly complex pregnancies.”