Women who are considering mothering a baby should try to reach a healthy weight before trying to become pregnant, an expert has advised.

In particular, those who have not taken healthy eating measures and reached an average weight should not consider crash dieting as a potential solution, according to a spokesperson from Tommy's.

Jacqui Clinton, Tommy's health campaigns manager, said: "By eating sensibly in pregnancy you will feel better and will be doing the best for your baby, with the added bonus that you may not have so many extra pounds to lose."

Ms Clinton added that mothers should avoid obesity when pregnant by taking daily exercise, as well as making small diet adjustments such as exchanging high-fat snacks for foods such as low-fat yoghurts or malt loafs.

Last month, the Royal College of Midwives and Netmums revealed that 70 per cent of mothers "ate for two" during pregnancy, while 41 per cent had weight concerns shortly before the birth of their child.