Healthy weight, diet and physical activity during pregnancy
The rates of women who are overweight or obese during pregnancy are increasing in Queensland. Steady weight gain during pregnancy is important for optimal development of the baby, however excess weight gain can have health risks for both baby and mother. Health professionals should provide pregnant women with information on diet and physical activity to encourage and support healthy gestational weight gain.
Risks of excess weight gain during pregnancy
Mothers who are carrying extra weight during pregnancy, and their baby, are at increased risk of short- and long-term health risks including:
- Gestational diabetes during pregnancy, and type 2 diabetes after pregnancy
- Gestational hypertension
- Difficulties during birth
- Miscarriage or stillbirth
- Large for gestational age baby
- Later life obesity and metabolic syndrome for baby
- No, or shorter duration of breastfeeding.
Risks of insufficient weight gain during pregnancy
Insufficient weight gain during pregnancy leads to an increased risk of:
- Low birth weight infant
- Preterm birth.
Gestational weight gain
Women should be given advice about appropriate weight gain during pregnancy. The amount of weight women aim to gain during pregnancy depends on their pre-pregnant body mass index (BMI). This can be calculated by dividing pre-pregnant weight (kg) by the square of the height (metres). If pre-pregnant weight is unknown, the first weight measurement of the current pregnancy can be used. Weight loss is not recommended during pregnancy.
Target weight gains during pregnancy:
|Pre-pregnancy BMI (kg/m2)||Rate of weight gain 2nd and 3rs trimester (kg/week)||Recommended total weight gain range (kg)|
|<18.5 underweight||0.51||12.5 to 18|
|18.5 to 24.9 normal weight||0.42||11.5 to 16|
|25.0 to 29.9 overweight||0.28||7 to 11.5|
|≥ 30.0 obese||0.22||5 to 9|
Health professionals should advise pregnant women of the recommended gestational weight gain (GWG) according to their prenatal BMI documented at their first antenatal appointment. Discuss and monitor weight gain regularly during antenatal care, and refer women to an appropriate professional for more tailored advice and support when gaining weight outside of the recommended GWG ranges.
Health professionals, including midwives, child health nurses and other clinicians who regularly see pregnant women are in an ideal position to ask about nutrition, supplementation and physical activity. It is a good opportunity to provide accurate information about nutrition and physical activity and the importance for optimal health of mother and child, in a non-judgmental way.
The Pregnancy Health Record pre-pregnancy BMI (PDF, 797kB), page 6, includes assessment, monitoring, advice and tools for weight before pregnancy and rate of weight gain during pregnancy. It is currently under review.
The Pregnancy weight gain chart < BMI 25 (PDF, 2MB) is for pregnant women in the healthy weight range and is a useful tool to monitor weight gain during pregnancy. It was developed by Royal Brisbane and Women’s Hospital, Metro North HHS and is currently undergoing evaluation.
The Pregnancy weight gain chart ≥BMI 25 (PDF, 3.1MB) is for pregnant women who are overweight or obese and is a useful tool to monitor weight gain during pregnancy. It was developed by the Royal Brisbane and Women’s Hospital, Metro North HHS and is currently undergoing evaluation.
The Mater Personalised Pregnancy Weight Tracker is an evidence-based resource developed by Mater Health Services to support healthy lifestyles during pregnancy through an increase in self-efficacy by self-awareness, goal setting, and self-monitoring. It makes use of the 5As framework for interventions (Ask, Advise, Assess, Assist and Arrange).
Healthy eating for pregnant women
Women don't need to 'eat for two' but they do need to eat twice as well. With only a 15–25% increase in requirements for energy (kilojoules), the quality (not so much the quantity) of dietary intake becomes important to meet increased nutrient needs.
Women require extra nutrients and energy during pregnancy for optimal weight gain and for development of the baby. To meet these increased requirements, the recommended number of serves for some food groups is increased. Encourage mothers to enjoy a wide variety of foods from all five food groups each day.
The Australian Dietary Guidelines (PDF, 2.6MB) recommend that women who are pregnant aim to consume the following on a daily basis:
- 5 serves of vegetables or legumes/beans of different types and colours
- 1 serve is equal to ½ cup cooked vegetables or legumes, 1 cup of salad, or ½ potato
- 2 serves of fruit
- 1 serve is equal to 1 medium or 2 small pieces of fruit
- 8 ½ serves of grain foods, mostly wholegrain or high fibre varieties
- 1 serve is equal to 1 slice of bread, ½ cup cooked rice or pasta, or 2/3 cup of cereal
- 3 ½ serves from lean meats, poultry, fish, eggs, tofu, nuts/seeds or legumes/beans
- 1 serve is equal to 65-80g cooked meat or poultry, 100g fish, 2 eggs, or 1 small handful of nuts/seeds
- 2 ½ serves of dairy foods, including milk, yoghurt, cheese or dairy alternatives (e.g. soy), mostly from reduced fat options
- 1 serve is equal to 1 cup of milk, 1 tub of yoghurt, or 2 slices of cheese.
- Aim to drink 3 to 3½ litres of water each day. Limit caffeine to 300mg per day (about 3 cups of coffee/6 cups of tea).
Other food and drinks are not needed and can contribute to excess weight gain. Encourage pregnant women to limit foods high in saturated fat, added salt and added sugars during pregnancy and while breastfeeding.
These recommendations are a general guide to assist women with healthy eating and meeting the additional nutrient requirements of pregnancy. The recommended serves may be too much for some women, and not enough for others. Pregnant women needing assistance with diet or weight management should be referred to a dietitian.
Requirements for some nutrients are increased during pregnancy and food is unable to provide as much as is needed. Daily supplementation is recommended for folic acid and iodine. Folic acid intake both pre-pregnancy and in the early stages of the pregnancy helps protect against neural tube defects, such as spina bifida, in the developing foetus. Iodine is important for the baby's brain and nervous system to develop. If supplementation has not commenced, encourage women to discuss this with their doctor or relevant healthcare professional.
Folic acid supplementation prevents risk of the baby being born with a neural tube defect and is important in the early stages of pregnancy.
- Inform women that supplementation of at least 400 micrograms per day from 12 weeks before conception and through the first 12 weeks of pregnancy reduces risk.
- Encourage and support women eating foods containing folate alongside supplementation (e.g. green leafy vegetables, broccoli, legumes, oranges, avocado, or fortified breads and cereals).
Iodine requirements are increased during pregnancy and breastfeeding. Iodine is an essential vitamin for brain development and the nervous system.
- Advise women who are pregnant to take an iodine supplement of 150 micrograms per day and continue to take supplementation during breastfeeding
- Encourage and support women to eat healthy foods containing iodine alongside supplementation (e.g. fortified bread, seafood, dairy foods). Advise when using table salt, always choose iodised table salt.
- Encourage women with pre-existing thyroid conditions to seek advice from their doctor before taking an iodine supplement.
Iron requirements are increased during pregnancy.
- During pregnancy, iron requirements increase by 50% from 18mg to 27mg per day.
- Routine supplementation during pregnancy is not recommended in Australia due to the fact that excessive iron intake can pose health risks to mother and child. Iron tablets should not be prescribed without relevant blood tests indicating a need for supplementation.
- Pregnant women should discuss checking their iron status with their doctor.
- It is recommended women consume iron-rich foods during pregnancy and are aware of foods that facilitate iron absorption.
- Iron rich foods include red meat, poultry, tofu, and iron-fortified cereals.
- Eating foods high in vitamin C (e.g. oranges, kiwi fruit, capsicum, broccoli) can facilitate iron absorption.
Apart from the recommended folate and iodine supplements, it is best to obtain nutrients from a varied diet consisting of nutritious foods from all five food groups.
Multivitamins designed for pregnancy generally contain small amounts of many different vitamins and minerals. Should women choose to take multivitamins during pregnancy they must be aware that these are for supplementation purposes only and are not comparable with/do not replace a nutritious diet.
Multivitamins not designed for pregnancy are not recommended as there are dangers associated with excessive doses of nutrients such as vitamins A (systemic toxicity), D (nausea and vomiting) and B6 (neuropathy).
As the immune system in pregnancy is suppressed, pregnant women are more susceptible to foodborne illness. Pregnant women have a higher risk of Listeriosis, caused by the bacterium Listeria monocytogenes. Listeriosis can be transmitted to the unborn child and possibly cause a miscarriage, premature birth or stillbirth.
As a precaution, pregnant women are advised to avoid specific foods that are more likely to contain Listeria bacteria. Foods that should be avoided include: unpasteurised dairy products and soft, semi-soft and surface ripened cheeses (e.g. brie, camembert, ricotta, fetta and blue cheeses), cold seafood, sandwich meats, pate, bean sprouts and packaged salads.
Some advice you can give includes:
- Wash raw fruit and vegetables thoroughly before eating.
- It is preferable to eat freshly prepared and cooked foods as opposed to pre-packaged foods as these have lower levels of bacteria.
- Avoid eating food if it has been made more than 24 hours ago. If you choose to eat food prepared the day before, it should always be reheated to steaming hot.
- Listeria is destroyed in normal cooking, so freshly cooked hot food is safe if eaten straight away.
- It is safe to eat foods that are listed as a higher risk provided it is heated above 74 °C for over two minutes.
Fish is an important part of a pregnant woman’s diet. It contains an excellent source of protein and is low in saturated fat. It also has high amounts of omega 3 and is a good source of iodine. However, a small number of fish contains higher amounts of mercury; therefore, Food Standards Australia New Zealand (FSANZ) has set the following guidelines for safe fish intake in pregnancy.
See: Mercury in fish – FSANZ (PDF, 73kB)
Pregnant women are advised:
- If consuming shark/flake, marlin or broadbill/swordfish, have no more than one serve (100g cooked) per fortnight and no other fish that fortnight.
- If consuming orange roughy (deep sea perch) or catfish, have one serve (100 g cooked) per week and no other fish that week.
Physical activity during pregnancy
Women who are pregnant can continue to exercise through most of their pregnancy. Women should be provided with information about the health benefits of physical activity.
Benefits of physical activity include: improved weight control; decreased risk of gestational diabetes; improved posture; less stress and anxiety; faster recuperation after labour and faster return to pre-pregnancy fitness and healthy weight.
The Australian Physical Activity Guidelines recommend that pregnant women undertake regular physical activity, as outlined below.
Encourage women to undertake regular physical activity including:
- 30 minutes of physical activity on most days of the week. If current physical activity is minimal, this should be increased slowly.
- Appropriate activities include aerobic exercises (walking, swimming, antenatal exercise classes), and light to moderate resistance exercises.
- Activities should be avoided if they involve lying on back, risk of falling or abdominal injury, or excessive stretching.
Body changes during pregnancy may affect exercise:
- Increase in body weight – changes in distribution and body shape may alter balance and coordination
- Loosening of ligaments – may increase injury risk
- Increase in resting heart rate
- Decrease in blood pressure (during second trimester) – cardiovascular adjustments take longer which may cause dizziness
- Weakening of pelvic floor – it is extremely important to do exercises that help conditioning the pelvic floor muscles from the start of pregnancy.
Encourage women to talk to their doctor or appropriate health care professional before beginning any new exercise activities or programs.
Alcohol, smoking and illicit drugs
Alcohol is not safe for developing babies. Not drinking alcohol is the safest option for women who are pregnant (See: Australian Government’s alcohol guidelines).
Smoking and use of illicit drugs (e.g. illegal drugs or prescription drugs for another person) can harm developing babies. It is best for parents, families and carers to avoid smoking and illicit drugs during the pregnancy.
Encourage women to talk to their health professional for assistance with avoiding use of alcohol, smoking or illicit drugs.
- Pregnancy Health Record pre-pregnancy BMI, Queensland Government (PDF, 797kB).
- Pregnancy weight gain chart < BMI 25, Queensland Government (PDF, 2MB)
- Pregnancy weight gain chart ≥BMI 25, Queensland Government (PDF, 3.1MB)
- Mater Personalised Pregnancy Weight Tracker, Mater Health Services
National and international guidelines
- Australian Dietary Guidelines
- Australia’s Physical Activity and Sedentary Behaviour Guidelines for Adults (18-64 years)
- Food Standards Australia New Zealand (FSANZ)
- Australian alcohol guidelines
- Clinical Practice Guidelines for the Management of Overweight and Obesity in Adults, Adolescents and Children in Australia
- Clinical Practice Guidelines: Pregnancy care guidelines – 2018
- Management of Obesity in Pregnancy