How overweight affects pregnancy and birth
16-minute read
Key facts
- Your weight during pregnancy and birth can mean you and your baby have a higher risk of complications.
- Your recommended weight gain during pregnancy depends on your pre-pregnancy BMI — your BMI is based on your height and weight.
- If you are living with overweight or obesity during pregnancy, your healthcare team can take steps to look after your health.
- You can support your health and the health of your baby by eating a healthy diet and staying active.
What is considered 'overweight' or 'obese'?
Your weight can impact your health. It is an important factor for your wellbeing during pregnancy and birth. The terms 'overweight' and 'obese' depend on your body mass index (BMI). This is calculated using your height and weight.
During pregnancy
When you are pregnant, your BMI is based on your height and weight before you became pregnant (pre-pregnancy). This can be measured at your first antenatal visit.
A pre-pregnancy BMI between 25 and 30kg/m2 means you are considered overweight for your height.
A pre-pregnancy BMI of 30kg/m2 or more shows you are living with obesity.
BMI is the best tool available to understand your weight. But, it can mean different things for different people. The BMI calculation does not tell the difference between weight from muscle and weight from fat. This means that if you are muscular or athletic, you may have a high BMI without being overweight.
When planning pregnancy care with your healthcare team, talk with them about your lifestyle and circumstances. That way, they can consider your BMI and your individual needs when recommending care for you.
There are many reasons why you may have a high BMI during pregnancy. Living with overweight or obesity while pregnant and giving birth means you may face some additional challenges. If you are affected by being overweight or living with obesity, support is available for your pregnancy. You and your baby deserve to receive quality care that best suits your situation.
What if I am overweight or living with obesity while pregnant?
You may have a higher risk of developing some complications during pregnancy. These complications can impact you and your baby.
These include:
- Gestational diabetes — high blood sugar levels during pregnancy
- Pre-eclampsia — high blood pressure during pregnancy
- Miscarriage — loss of a pregnancy
- Thrombosis — blood clots
If you are living with overweight or obesity during pregnancy, you also have a higher risk of influenza (or 'the flu').
You are also more likely to have nutritional deficiencies, like low vitamin D or iron.
What if I am overweight or living with obesity when giving birth?
Living with a higher BMI can impact you and your baby. You may have a greater chance of having complications while giving birth.
These include:
- heavy bleeding after giving birth — also known as postpartum haemorrhage
- shoulder dystocia — your baby’s shoulder becomes stuck during birth
- longer labour — this mostly affects the first stage of labour
Induction of labour
If you are living with a higher BMI, waiting for labour to start naturally can increase the risk to you or your baby’s health. There is a higher chance that your doctors will offer to start your labour using artificial methods. This is called inducing your labour.
Obesity also lowers the chances of successfully inducing your labour.
Assisted birth
Obesity can increase the chance you will need to have an assisted birth. This is when your maternity care team use medical techniques or instruments to help you to give birth. This includes caesarean sections.
Complications with anaesthetics
Obesity and overweight can make an epidural take longer to relieve pain during labour. It can also make it more difficult to give you general anaesthetic.
Will being overweight or obese affect my baby?
If you are living with obesity, your baby has an increased risk of developing some complications.
These include:
- lower Apgar scores (a measure of newborn health)
- birth differences
- stillbirth or neonatal death
Your baby is also more likely to have a large birth weight of 4kg or more. This is called fetal macrosomia.
Your baby is more likely to need to spend some time in the neonatal intensive care unit (NICU).
Your baby also has a higher chance of developing diabetes and obesity during childhood or adulthood.
How much weight should I gain during pregnancy if I have a higher BMI?
If you live with overweight or obesity, the recommended weight gain during pregnancy is less than if you have a BMI within a healthy weight range before becoming pregnant.
Here are the recommendations for weight gain during pregnancy based on BMI.
| Pre-pregnancy BMI | Ideal weight gain during pregnancy | |
|---|---|---|
| Healthy weight range | 18 to 24.9 | 11.5kg to 16.0kg |
| Living with overweight | 25 to 30 | 6.8kg to 11.3kg |
| Living with obesity | above 30 | 5.0kg to 9.1kg |
If you are having twins or multiple babies, your ideal weight gain may be different.
Talk to your doctor or midwife about how ideal weight gain in pregnancy applies to you.
How can I manage my weight during pregnancy if I live with a higher BMI?
If you are concerned about your weight, ask your doctor or midwife how they can help you.
Before conception, if you are living with obesity, even a small amount of weight loss can improve your and your baby's health.
During pregnancy, you should not try to lose weight. Instead, with your doctor’s advice you can try to limit weight gain during pregnancy.
Weight-loss medicines are not recommended during pregnancy.
The best way you can prevent too much weight gain during pregnancy is by maintaining a healthy diet and staying physically active.
A dietitian can help you with a nutrition plan. A nutrition plan should suit your nutritional needs, lifestyle and health conditions. It can also tell you what foods to avoid during pregnancy.
Before doing exercise during pregnancy, you can talk to:
They can help you manage your weight and exercise safely.
Negative stigma around being overweight or living with obesity can also impact your pregnancy and birth. Speak to your doctor or midwife. They can recommend services and healthcare professionals who can best support you through your pregnancy care.
NEED TO LOSE WEIGHT? — Use the BMI Calculator to find out if your weight and waist size are in a healthy range.
How will doctors and midwives manage my pregnancy?
Your healthcare team will likely take some extra precautions with your pregnancy if you have a higher BMI.
This may include:
- giving advice on how to manage weight gain during pregnancy
- recommending nutrition supplements to suit your circumstances
- doing extra ultrasound scans to monitor your baby
- testing for gestational diabetes early in your pregnancy and again at 28 weeks of pregnancy
- frequently monitoring you for signs of pre-eclampsia
- doing an anaesthetic assessment, in case you will need a caesarean section
Ask your doctor or midwife how often you should come in for a pregnancy health check. They can also advise if you should see a specialist obstetrician.
Remember — the care you receive during your pregnancy is your choice. It’s important to speak to your doctor or midwife about your options. Be sure to ask any questions you may have about the care they recommend so that you are well informed. This way, you can work with them to make shared decisions about your care.
Where can I have my baby if I am living with overweight or obesity?
If you are living with overweight or obesity, you may have fewer options for where to have your baby. Not every hospital will meet your needs during labour.
It is important that you speak to your doctor or midwife before deciding where you want to give birth. You can ask them about hospitals and birthing centres that can best support you during labour.
Suitable hospitals may have specialist equipment to help you move during labour, such as a hoist. They may also have anaesthetists or surgeons who are familiar with the possible complications you may experience during labour.
Hospitals have different 'levels', which set the level of care they can provide:
- If you live with overweight, you can usually give birth at hospitals that are level 3 and above.
- If you live with obesity, you can usually give birth at hospitals that are level 4 and above.
Options for the type of hospital that you can choose may be different depending on where you live in Australia. Your options can also depend on if you receive public or private healthcare during your pregnancy.
Generally, home births are not recommended for people living with obesity because of the higher chance of complications.
What precautions may your doctor or midwife take during labour?
During labour, your doctor or midwife may recommend that your baby’s heart rate be monitored.
They may ask to externally monitor your baby’s heart rate. This involves placing a device on your stomach. If you have a BMI above 40, they may recommend continuous electronic fetal monitoring (CEFM).
Sometimes, it can be difficult to monitor your baby's heart rate if you are living with obesity. If your healthcare team has difficulties, they may recommend monitoring your baby's heart rate internally. If you agree, your doctors can use a device called a fetal scalp electrode. This will be placed through your vagina to your baby. The electrode is a very thin wire that is placed into the skin of your baby’s scalp. This can help your doctor monitor your baby’s heart rate.
If you have any questions about monitoring your baby’s heart rate, ask your doctor or midwife.
They may also use an ultrasound machine to monitor your baby’s position.
Will I be able to breastfeed my baby if I am affected by overweight?
If you live with overweight and obesity, you can successfully breastfeed your baby, but you may have some additional challenges.
If you are having difficulty initiating breastfeeding, talk to your midwife for advice. They can also refer you to a lactation consultant for breastfeeding support.
What can I do to maximise my chance of having a healthy pregnancy and birth?
It’s important to create a healthy lifestyle for yourself and for your baby by doing your best to eat well and exercise regularly.
It can be very hard to change old habits. Any improvements can help you have a more comfortable pregnancy and easier birth. This will also improve your baby's health.
Eating well
Try to maintain a balanced diet as recommended by the Australian Guide to Healthy Eating. This includes eating a range of foods, including:
- vegetables
- fruit
- wholegrain foods — such as wholegrain bread and crackers
- low-fat milk products — such as light milk and low-fat cheese
- non-fatty meat
- oily fish
These foods give you important vitamins, minerals and proteins. This can keep your body healthy and functioning well before, during and after pregnancy. Eating well can support a healthy pregnancy.
Drink water
Make sure you drink enough water.
If you are pregnant, try to drink at least 9 cups of water per day.
Keep active
Being active can prepare your body for a healthy pregnancy. Having healthy habits can help you keep active while pregnant.
Aim for at least 30 minutes of physical activity a day, most days of the week. You don’t have to do these 30 minutes all at once.
You may choose to do these at one time or in several shorter sessions.
You can try:
It's best to speak to your doctor or dietitian before making any major lifestyle changes. They can help you start exercising safely.
Look after your mental health
It’s also important to feel mentally well to prepare for pregnancy and birth.
Pregnancy can be physically and mentally overwhelming. It can impact your mental health. Depression can lead to weight gain. Looking after your mental health can help you cope with any difficulties during pregnancy.
If you feel that you need mental health support, speak to your doctor. They can give you advice and refer you to a mental health professional if needed.
Receiving mental health support before and during your pregnancy can:
- help you achieve a healthy weight
- improve your mental wellbeing
- help you prepare for parenthood
It’s important to feel physically and emotionally safe during your pregnancy. You can talk to your doctor or mental health professional about trauma-informed care during pregnancy.
FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.
Resources and support
- The Royal Women's Hospital website has information on weight and exercise in pregnancy.
- The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) website also has information on weight gain and exercise during pregnancy.
- For advice and to connect to local mental health services, call Medicare Mental Health on 1800 595 212. Check the operating times.
Languages other than English
- You can read information from the National Diabetes Services Scheme about pregnancy and diabetes in multiple languages through the Health Translations website.
- You can also read about growing a healthy baby in Arabic, Dari, Dinka and Karen on the Safer Baby website.
Speak to a maternal child health nurse
Call Pregnancy, Birth and Baby to speak to a maternal child health nurse on 1800 882 436 or video call. Available 7am to midnight (AET), 7 days a week.
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Last reviewed: October 2025
