Pregnant after weight-loss surgery

If you’ve had weight-loss surgery before getting pregnant, you are likely to have a safe, straightforward pregnancy and birth.

Ideally, you should wait for at least 12 to 24 months after surgery and once your weight has stabilised before getting pregnant. But try not to worry if you’re pregnant before then. Many women and birthing people have babies safely before 12 months.  

Is pregnancy safe after weight-loss surgery?

Yes, it is. You are less likely to have complications such as gestational diabetes, high blood pressure and a baby with a larger birth weight than if you had a higher BMI (body mass index).  

Losing weight after surgery can reduce risks and help you have a safer pregnancy.

How can I make sure my pregnancy is as safe as possible?

Talk to your health care team so you can get the best advice and support. Contact your GP or midwife and your weight-loss surgery team as soon as you know you’re pregnant. If you had your operation abroad, ask your GP if you need to be referred to a UK specialist weight-loss surgery clinic. If you’ve already been discharged by your weight-loss surgery team, ask your midwife whether you should contact them again.

Your care should be based on the type of surgery you had and when you had your operation. If it was more than 18 months ago, you may just need to follow the usual pregnancy advice on healthy eating and exercise

If your surgery was less than 12 months ago, you will need more specific support and advice. 

Early Contact

It’s important to talk to your care team as soon as you know you’re pregnant so you can get the best advice. This includes your midwife and your weight-loss surgery team.

Will my diet after weight-loss surgery be healthy for me and my baby?

You may worry that if you eat less after surgery, you won’t be getting enough food to support your baby’s development. But this is unlikely because your baby takes what they need for growth from you. You do not need to eat any extra food in the first 2 trimesters of pregnancy. In the third trimester you may need to eat an extra 200 calories per day.

How you eat is likely to differ from before you had surgery. You may be used to taking vitamin and mineral supplements every day. Talk to your weight-loss surgery team about your diet and the supplements you’re taking to make sure these are safe. 

Ask them about anything that worries you and follow their advice on healthy eating. They will be able to explain what amounts and types of foods will give you enough nutrients to keep you and your baby healthy.

Your midwifery team also needs to know what diet advice you’ve been given by your weight-loss surgery team, so don’t forget to tell them.  

Supplements needed in pregnancy after weight-loss surgery

You will need vitamin and mineral supplements if you get pregnant after any type of weight-loss surgery. You may also need regular blood tests to check your nutrient levels during each trimester.  

Talk to your healthcare team about what vitamin and mineral supplements you will need and how your blood levels will be monitored during pregnancy.  

Folic acid  

All pregnant women and birthing people are advised to take 400mcg of folic acid every day until they are 12 weeks pregnant. If you’ve had weight-loss surgery, you may need a higher dose of folic acid

Folic acid can help prevent birth defects known as neural tube defects, including spina bifida. The higher dose is only available on prescription, so talk to your weight-loss surgery and midwifery team to see if you need it.

Your weight-loss surgery team can give you guidance on your diet and the supplements you’re taking to make sure you’re on the right track.  

Am I going to put all the weight back on during pregnancy?

It is unlikely that you’ll put all the weight you lost back on during pregnancy.

It is natural to gain some weight when you are pregnant. This is because your baby is growing and surrounded by amniotic fluid and placenta. Your body is producing more blood, your breasts are getting bigger, and so are your muscles and bone mass.

Weight gain is different for everyone during pregnancy, and it is something many people worry about, whether they had weight-loss surgery or not.

Chat with your midwife and weight-loss surgery team about how you feel so they can support and advise you. Remember they are there to help.

Changes to your weight will depend on several factors, including:

How long it has been since your weight-loss surgery

You may carry on losing weight if it hasn’t been long since your operation. If this is the case, ask your surgery or midwife for advice. If it has been 18 months or more since your surgery, and your weight is now stable, you may need to look after your weight in the same way as the average person does. Speak to your midwife for more advice

The type of surgery you had

Some weight-loss surgery teams may adjust your gastric band if you are pregnant, by removing fluid from it, and you may gain weight as a result. This can be managed as normal through healthy eating and exercise.

I worked so hard to lose weight that, although I was thrilled to be pregnant, I was also scared that my body would be out of control again. But I talked to the bariatric nurse and my GP and it’s been fine.


When should I be concerned?

Pregnancy can cause weird and wonderful changes to your body. Many are perfectly normal but, following surgery, some symptoms should be checked out quickly with your surgery team to make sure all is well.

I feel sick

Although nausea and/or sickness in early pregnancy are common, vomiting in pregnancy following weight-loss surgery should be checked out. If you are having regurgitation and vomiting due to food intolerance, you should discuss this with your weight-loss surgery team.

I’m in pain

Any severe pain, particularly in the stomach, needs to be investigated.

I am losing weight very quickly

If you had your operation in the last 12 to 18 months, you may still be losing weight because of it. But if the weight loss is faster than expected, go back to your weight loss and midwifery teams for support, as you should not be actively losing weight during pregnancy.

If your BMI is over 30

If you have a BMI over 30, you will be monitored more carefully by your midwifery team because there is a higher risk of pregnancy related complications, such as increased blood pressure, gestational diabetes and blood clots. This extra care and support to ensure you have the healthiest pregnancy possible.

Glucose tolerance test (OGTT) after weight-loss surgery

Women and birthing people with a BMI of over 30 are usually given a glucose tolerance test (OGTT or mini-GTT) to check for gestational diabetes. This involves having a sugary drink followed by blood tests to see how your body copes with the sugar.

If you had bypass surgery, you are not advised to have an OGTT as there is a risk of having a reaction called ‘dumping syndrome’. You must let your midwife and consultant know about your weight-loss surgery. Contact your weight-loss surgery team for guidance and to arrange other types of tests or monitoring.  

Find out more about being overweight in pregnancy. 

Ouyang, DW et al (2023) Fertility and pregnancy after bariatric surgery. Up To Date.

NICE (2010) Weight management before, during and after pregnancy: Public health guideline 27. National Institute for Health and Care Excellence

Chapmon K, Stoklossa CJ, Benson-Davies S; Integrated Health Clinical Issues Committee of the American Society for Metabolic and Bariatric Surgery. Nutrition for pregnancy after metabolic and bariatric surgery: literature review and practical guide. Surg Obes Relat Dis. 2022 Jun;18(6):820-830. doi: 10.1016/j.soard.2022.02.019. Epub 2022 Mar 6. PMID: 35379565.

O'Kane, H et al (2020) British Obesity and Metabolic Surgery Society Guidelines on perioperative and postoperative biochemical monitoring and micronutrient replacement for patients undergoing bariatric surgery—2020 update. Bariatric Surgery. 2020. 

Review dates
Reviewed: 05 July 2023
Next review: 05 July 2026