Myths about pregnancy and weight—such as that pregnant women need to “eat for two”—need to be challenged by GPs, midwives, and other healthcare workers, says new guidance from the UK National Institute for Health and Clinical Excellence (NICE).

Obese women and their unborn babies face serious health risks, including a raised risk of miscarriage, stillbirth, pre-eclampsia, and gestational diabetes, it says. Women need reliable information on how to manage their weight before, during, and after their pregnancy.

The team that produced the guidance says that healthcare professionals such as GPs and midwives don’t routinely provide this advice and that many healthcare professionals are …