A quarter of pregnant women seen by the Blackpool Teaching Hospitals NHS Foundation Trust are obese at the time of their first screening.
Health professionals have warned that women could be putting both their own and their baby’s health at risk by not losing weight before getting pregnant.
According to data from NHS Digital, around 3,060 women were weighed at their first antenatal booking appointment with the trust in the 12 months to April 2018.
Of these, 25 per cent were found to have a Body Mass Index (BMI) of 30 or above, placing them in the obese range.
A further 27 per cent were deemed overweight, with a BMI of 25 or over.
When the number of underweight women is taken into account, the figures mean that fewer than half of all expectant mothers seen by the trust were considered to be at a healthy weight at this stage of their pregnancy, which is typically between the ten and 12 week mark.
According to both the NHS and the Royal College of Midwives (RCM), obese women are more at risk of a range of complications during pregnancy, including miscarrage, diabetes and premature birth.
Tam Fry, spokesman for the National Obesity Forum, described the numbers as “saddening”.
He added: “Getting into shape before a conception and ensuring that you are eating healthily has been a long advocated message but too few heed it. A woman unhealthily overweight at booking in can not only be a health risk for her foetus but also for herself.”
Clare Livingstone, Professional Policy Advisor at the RCM, said: “While most overweight and obese women will have a straightforward pregnancy and birth, the risk of complication is increased to both mother and baby.”
Last month, The Gazette revealed that health chiefs were considering offering shopping vouchers to pregnant women in the resort in a bid to persuade them to give up smoking.
It comes after nearly a third of expectant mums in the resort continue to smoke.
Trainers would also provide mums-to-be with intensive support throughout pregnancy to give up smoking.