The average pregnancy is counted as 40 weeks, starting from the first day of the mother’s last period. Pregnancy is divided into three trimesters, with different stages in each. The development of a pregnancy can be followed week by week, but it’s important to remember the experience varies for every mother and baby.…
Diet and pregnancy
Why is diet so important during pregnancy?
During pregnancy, you may need to pay extra attention to your diet, to make sure both you and your baby get all the nutrients you need. Not only does your baby need a range of nutrients as essential building-blocks for their development, there is increasing evidence that what a mother eats during pregnancy can affect their baby's health throughout their lives.
It's also necessary to be more aware of food safety during pregnancy, because certain infections can pose a risk to your developing baby. While there's no need to be fearful or worry about foods causing harm, being aware of how to eat a balanced healthy diet and taking a few precautions regarding some foods that can cause problems is an important part of looking after yourself during pregnancy.
During the first trimester of pregnancy, your energy needs are generally the same as usual. However, as your pregnancy progresses, you'll need more energy. It is recommended you increase your intake of grain-based foods and protein-rich lean meats (or alternatives).
By eating a balanced amount of the five food groups listed below, you'll get the nutrients and energy you and your baby need.
Serves per day
Pregnant women 19-50
Pregnant women 18 or under
Vegetables and legumes
Lean meats and alternatives
Dairy foods and alternatives
Eating a healthy and balanced diet can be challenging during pregnancy, particularly if you experience morning sickness. If you are having difficulties, discuss it with your doctor or midwife. Consulting a dietitian can also be helpful.
Weight gain during pregnancy
Weight gain is a normal and expected part of pregnancy. While the amount of weight varies between women, it's important to keep it within a healthy range.
Gaining too little weight may interfere with the baby's development, leading to a low birth weight and other health risks. Gaining too much weight may increase the mother's risk of complications during pregnancy such as gestational diabetes. It may also contribute to a baby's risk of being overweight or obese throughout their lives, which can raise the risk of a range of health problems such as cardiovascular disease and type 2 diabetes.
A healthy amount of weight gain during pregnancy depends on your weight before you become pregnant. For women who have a pre-pregnancy weight in the healthy range (a body mass index of 18.5-25), the recommended overall weight gain in pregnancy is 11.5-16 kilograms.
For women who carry extra weight, weight loss is generally not recommended during pregnancy. Rather, a reduced amount of weight gain may be suggested as your target. For women who are underweight, a greater-than-average weight gain may be recommended.
Your doctor or midwife can discuss what an appropriate weight gain throughout pregnancy is for you.
Special nutritional needs
Although a balanced, varied diet will supply most of the nutrition you need during pregnancy, there are some nutrients that are important for the baby's development that are needed in greater amounts.
You may be advised by your doctor or midwife to take a supplement during pregnancy (or before, if you are planning to get pregnant). However, before taking supplements, it's important to talk to your healthcare professional first, so they can make sure they are suitable for your needs.
Pregnancy increases the need for iron. Iron is found in a range of foods, including red meats, poultry, eggs, fish, cooked legumes, green vegetables and dried fruits.
In some cases, pregnant women may be advised to take a supplement; however, many women can get all the iron they need from their diets. Women who eat a diet without animal-based foods (vegetarian, vegan) may need to take particular care, as iron from non-meat sources is not absorbed as well by the body. Consuming foods high in vitamin C, such as orange juice, at the same time can help with iron absorption, while foods with caffeine can interfere with it.
Folate is a form of vitamin B. Having adequate levels of folate is particularly important in the first trimester of pregnancy because it helps to protect babies from neural tube defects such as spina bifida. It is called folic acid when it is in the supplement form or added to foods.
Pregnant women are advised to take a daily 400-microgram supplement of folic acid and to eat foods that are rich in folate during the planning of pregnancy and in the first trimester. For some women (particularly if there is a history of neural tube defects in their family), a higher level of folate may be recommended.
Foods that naturally contain high levels of folate include:
- Green vegetables such as broccoli, spinach, brussel sprouts and asparagus;
- Legumes such as chickpeas, dried beans, lentils and peas, and;
- Bran flakes and wheatgerm.
Some foods, such as most breads (although not those labelled organic), some breakfast cereals and orange juices have folic acid added.
Iodine is a mineral required by the thyroid gland to produce thyroid hormones. If you consume too little iodine during pregnancy, it can have serious consequences for the baby's growth and brain development, causing a condition called congenital hypothyroidism.
Most pregnant women can obtain enough iodine from their diets, but some women may be advised to take an iodine supplement when planning a pregnancy, throughout pregnancy and while breastfeeding.
Iodine can be found naturally in foods including fish and seafood. It is also added to most breads (not organic) and to some salt, called iodised salt. Natural sea salt does not contain significant levels of iodine.
Calcium is an important nutrient for the strength of bones. Particularly during the latter stages of pregnancy, the baby needs large amounts and if you are not consuming enough calcium, it will be drawn from your own bones. This can increase your risk of developing osteoporosis later in life.
You can obtain the required calcium from your diet by consuming two-and-a-half serves of dairy foods or alternatives fortified with calcium every day. This includes milk or soy milk (with added calcium), yoghurt and hard cheeses.
Fish and mercury
Fish is a healthy food that is a rich source of nutrients such as iodine and omega-3 fatty acids, which are important for a baby's brain development. It is recommended that women eat two to three serves of fish a week during pregnancy.
However, it is important to be careful with consuming certain types of fish because they can contain elevated levels of mercury. Mercury is present naturally in the environment in low levels. Large, longer-living fish, particularly those that eat other fish, can build up high levels of mercury (methylmercury). These fish include shark (flake), swordfish (broadbill), marlin, catfish and orange roughy.
Eating too much of these fish can cause health problems for anyone, but pregnant women need to be particularly careful because mercury can pass through the placenta and damage the developing central nervous system (the brain and nerves in the spine) of the baby.
For shark, swordfish and marlin, it is recommended that pregnant women consume no more than one serve per fortnight and have no other fish in that time. For catfish and orange roughy, no more than one serve per week and no other fish in that time is advised.
Foods and allergy
Some foods, particularly tree nuts such as peanuts, are strongly associated with allergy. If you are already allergic to these foods, it is important to avoid eating them as usual. However, avoiding foods such as nuts does not change the baby's risk of developing allergies to them.
While everyone is advised to drink plenty of water, during pregnancy you tend to need more than usual. Drink water frequently. If you are travelling overseas, follow food safety guides and avoid tap water due to potential contaminations.
Alcohol, caffeine and smoking
Just as it is important to take care with medications during pregnancy, being aware of the detrimental effects of alcohol and other substances on the developing baby can help you make informed choices about what you consume.
National Health and Medical research Council (NHMRC) guidelines advise that there is no established safe level of alcohol consumption during pregnancy, so women who are pregnant or breastfeeding are recommended not to drink any alcohol.
A range of developmental problems have been linked to the consumption of alcohol during pregnancy, including foetal alcohol syndrome.
Caffeine is present in a range of foods and drinks, including coffee, tea, chocolate, cola and energy drinks. There is some evidence that consuming large amounts of caffeine may be linked to an increased risk of miscarriage and premature labour. Recommendations vary, but it is suggested that pregnant women consume no more than 200-300mg of caffeine a day. That is around four cups of tea or two cups of coffee. Avoid beverages that are likely to contain large amounts of caffeine, such as energy drinks or espresso coffees with double shots.
Diet and symptoms of pregnancy
You can help to manage these symptoms by following diet and lifestyle recommendations such as:
- Eating a wide variety of fibre-rich foods such as vegetables, legumes and foods made from wholegrains and drinking plenty of water to reduce constipation;
- Eating small meals to help reduce symptoms of morning sickness and reflux, and;
- Being aware that how you move can influence your symptoms. In early pregnancy, getting up slowly can help to reduce morning sickness, while avoiding bending over or going to bed soon after a meal in later pregnancy can help to reduce reflux symptoms.
Food safety during pregnancy
Certain infections can cause issues during pregnancy or can be harmful to your baby's development. For this reason, even though everyone needs to be careful with food storage and hygiene to prevent food poisoning, when you are pregnant you need to take extra care.
Organisms that can cause serious problems during pregnancy include:
- Listeria - while rare, infection with this bacteria, called listeriosis, can lead to miscarriage, premature birth and stillbirth;
- Salmonella - a type of bacteria that is a common cause of food poisoning. In rare cases, it can cause miscarriage, and;
- Toxoplasmosis - while this parasite is rare and infection is more commonly caused by contact with cat faeces, it can be transmitted through undercooked meats and unwashed fruits and vegetables. Toxoplasmosis can cause damage to the developing brain and eyes of the baby.
Good food hygiene and handling habits can help to reduce the risk of food-related illness and are important for everyone to practise. These include:
- For food that needs to be chilled, keep it in the fridge, under 5ºC and minimise the time it spends outside;
- Wash your hands before handling food and keep utensils, equipment and benches clean;
- Cook food to above 60ºC and hotter if required, and make sure it cooks or reheats right through to the middle, and;
- Follow labels such as use-by dates.
During pregnancy, you can reduce your risk by eating only freshly prepared and well-cooked foods. Wash fruit and vegetables well and eat them soon after preparation. Put any leftovers in the fridge promptly and eat within a day.
It is also recommended that you take extra precautions by avoiding:
- Raw meats, raw fish and seafood, including sushi;
- Processed meats (such as ham and salami), unless cooked to 75ºC and eaten soon after;
- Cooked meats that have been stored cold for an unknown period (such as cold chicken for sandwiches);
- Foods containing raw eggs;
- Paté and other meat spreads;
- Soft and semi-soft cheeses such as ricotta, brie, feta and blue cheeses, unless cooked to 75ºC and eaten soon after;
- Soft-serve ice-cream;
- Unpasteurised dairy products;
- Sprouts such as broccoli sprouts, snowpeas or alfalfa, when not thoroughly cooked;
- Pre-packaged salads and sandwiches, and;
- Stuffing from chicken and other poultry, unless cooked separately.