Pregnancy can be a difficult time for meeting nutrition needs. There are many nutrients needed in higher amounts than usual to support the developing foetus. There are also several foods that government health bodies recommend avoiding, as pregnant women are often more susceptible to food-borne illness due to changes in hormones and their immune systems. This can result in some challenges to optimising nutrition during pregnancy. Some of these challenges are very common, and there are plenty of strategies to help with their management.

Iron deficiency anaemia

Iron requirements are significantly higher during pregnancy; however, there are physiological changes that increase iron absorption to help meet this need. Despite this, iron deficiency anaemia (IDA) is a common occurrence in pregnancy. The World Health Organization (WHO) estimates that 13.9% of pregnant women in Australia had some form of anaemia in 2023, with IDA being the most common.(1) Consuming the recommended dietary intake (RDI) of 27 mg iron per day can help prevent IDA during pregnancy.(2) It is important to monitor serum iron levels throughout pregnancy to identify those with, or at risk of, IDA. The Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG) recommend those with IDA during pregnancy take a specific iron supplement, not as part of a multivitamin, of at least 60 mg per day.(3) Iron supplements are best absorbed when taken with vitamin C-rich foods, such as orange juice.(4)

Listeria

Listeria infection can be caused by eating foods contaminated with the bacterium Listeria monocytogenes. Listeria infection is more likely during pregnancy due to pregnancy-related immune suppression. Infection can cause miscarriage, still birth, premature birth or a very ill infant at birth.(5) High-risk foods for Listeria contamination include:

• Pre-cooked meat products eaten without further cooking (e.g. pâté, sliced deli meat and chicken)
• Chilled seafood (e.g. smoked fish, smoked mussels, oysters and raw seafood)
• Pre-prepared salads (e.g. fruit salads and coleslaw)
• Unpasteurised dairy products and soft cheese products (e.g. camembert, ricotta, brie, and soft-serve ice-cream)

Food Standards Australia and New Zealand (FSANZ) recommend avoiding these high-risk foods during pregnancy and using safe handling practices during food preparation.(5) To learn more, visit the Food Standards website.

Mercury

Fish can still be enjoyed as part of a healthy diet during pregnancy. However, in addition to being cooked and eaten immediately, it should also be consumed in moderation. Some fish contain high levels of mercury that can impair nervous system development in the foetus if consumed in large amounts.(6) FSANZ provides guidelines and recommendations for the amount and types of fish with higher mercury levels that can be eaten during pregnancy. They recommend:

“1 serve per week of Orange Roughy (Deep Sea Perch) or Catfish and no other fish that week, OR 1 serve per fortnight of Shark (Flake) or Billfish (Swordfish/Broadbill and Marlin) and no other fish that fortnight.”(6)

If other types of fish that are lower in mercury are consumed during pregnancy, it is recommended to avoid eating any of the types mentioned above.(6) For a patient-friendly resource, see the FSANZ ‘Mercury in Fish’ brochure.

Vegetarian diets and pregnancy

A well-planned vegetarian diet can support nutritional health during pregnancy. A vegetarian diet often includes more fibre, wholegrains, and less fat than non-vegetarian diets.(7) A vegetarian diet ideally replaces meat products with appropriate alternatives such as legumes, tofu, eggs and dairy products to help meet the additional protein, iron and zinc needs during pregnancy. However, even with a well-planned vegetarian diet, it can be difficult to meet the required vitamin B12 levels during pregnancy. RANZCOG recommend vegetarians take a vitamin B12 supplement throughout pregnancy to meet the RDI of 2.6 µg per day.(3)

Alcohol

Consumption of alcohol while pregnant can harm the developing foetus.(8) There is no safe level of intake currently understood. The National Health and Medical Research Council (NHMRC) states, “to prevent harm from alcohol to their unborn child, women who are pregnant or planning a pregnancy should not drink alcohol”.(8) The safest approach is to completely stop drinking alcohol during all stages of pregnancy. For more information, visit EveryMomentMatters.org.au.

Caffeine

In Australia, FSANZ recommends caffeine intake be limited to less than 200 mg per day during pregnancy.(9) Caffeine passes through the placenta and to the developing foetus. There is still uncertainty about whether caffeine directly harms the foetus, but high intake of >300 mg/day may increase the risk of several complications, such as low birth weight.(10) Common sources of caffeine in the Australian diet include coffee (~80–120 mg in 250 mL), black tea (~65–105 mg in 250 mL), cola drinks (~40–49 mg in a 375 mL can), and energy drinks (~80–160 mg in a 250 mL can). There is significant variation in caffeine content between brands, so it is important to read nutrition labels before trying a new product. Some medications, herbal remedies and supplements also contain caffeine and contribute to the 200 mg/day limit.

Food aversions and pregnancy

Some experience a loss of appetite or aversion to particular foods during their pregnancy. Both are more common in the first trimester but can occur at any point during pregnancy. It is important to work with the changing food preferences while still following pregnancy recommendations from the Australian Dietary Guidelines.(2) A formulated supplementary food may be beneficial during pregnancy in circumstances where it is difficult to meet nutritional needs.