Pregnancy information

Overweight and pregnancy

Being overweight when you're pregnant increases the chance of some complications such as gestational diabetes. Make sure you go to all your antenatal appointments so your pregnancy team can monitor the health of you and your baby.

Your weight during pregnancy 

If you are obese, usually defined as having a body mass index (BMI) of 30 or above, and pregnant, do not try to lose weight during your pregnancy. It will not reduce the chance of complications and may not be safe.

The best way to protect you and your baby’s health is to go to all your antenatal appointments. This is so your midwife, doctor and any other health professionals can help with any problems you might face and take steps to prevent or manage them.

Eating and Exercise

It's important to eat a healthy, balanced diet and do some physical activity every day. You should be offered a referral to a dietitian or other health professional for advice on healthy eating and physical activity. Being physically active in pregnancy will not harm your baby.

Eating healthily (including knowing what foods to avoid in pregnancy) and doing activities such as walking or swimming is good for all pregnant women.

If you were not active before pregnancy, it's a good idea to consult your midwife or doctor before starting a new exercise plan when you're pregnant.

Your care in pregnancy

If you become pregnant before losing weight, you'll be tested for gestational diabetes.

You may also be referred to an anaesthetist to discuss issues such as pain relief in labour. You're more likely to need an epidural, because very overweight women are more likely to have an instrumental delivery (ventouse or forceps or a caesarean section), and it can be difficult for an epidural to be given.

If you're overweight, discuss your birth options with a midwife or doctor. Ask if there are any particular safety concerns for you around giving birth at home or in a birthing pool.

You may be advised to give birth in a hospital where there's easy access to medical care if you need it.

Find out more about your options on where to give birth.

Possible problems if you're overweight in pregnancy

Being overweight increases the chance of complications for pregnant women and their babies. The higher a woman's BMI, the higher the chance of complications. The increasing chances are in relation to: 

You are also more likely to need an instrumental (ventouse or forceps) delivery, and an emergency caesarean section.

Possible problems for your baby if you're overweight in pregnancy

Problems for your baby can include being born early (before 37 weeks), and an increased chance of stillbirth.

There is also a higher chance of your baby having a health condition, such as a neural tube defect like spina bifida. 

Bear in mind that although the chance of these problems is increased if your BMI is 30 or above, most women who are overweight will have a healthy baby.

You can find out more in a leaflet from the Royal College of Obstetricians and Gynaecologists, called Why your weight matters during pregnancy and after birth.

Last Updated: 12/07/2023 11:28:22
The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website