The Royal College of Obstetricians and Gynaecologists (RCOG) had warned overweight women to slim down before trying for a baby.
In a patient leaflet, RCOG says women should lose extra weight BEFORE they conceive, as dieting when pregnant is dangerous.
The Telegraph reports that around 40,000 'severely obese' women give birth every year, and have an increased risk of blood clots, gestational diabetes, high blood pressure and pre-eclampsia, as well as the threatening the pregnancy and the health of their baby.
Philippa Marsden, Chairman of the RCOG's Patient Information Committee, told the Telegraph: "This new advice gives women information about the risks of being overweight during pregnancy and giving birth but more importantly focuses on how women can work together with their health care team to reduce these risks. It also details the extra care a woman should have during her pregnancy if she has a raised body mass index."
She adds that dieting whilst pregnant is not recommended even for obese women, and that 'healthy changes' to diet will help limit weight gain during pregnancy.
The leaflet also states that there in no need to 'eat for two' as pregnant women only need extra calories in their third trimester, and then only 200 more - the equivalent to two pieces of toast.
Did you diet in order to conceive?