Nutrition and Exercise
Folate & Pregnancy Multivitamins
The current recommendations are that all women who are planning to become pregnant should take 0.5mg of folate daily for at least a month prior to falling pregnant and continue this for at least the first 13 weeks of pregnancy. Folate helps prevent neural tube defects in the developing fetus. If you were not already taking folic acid before you became pregnant, you should commence this as soon as possible. A standard pregnancy multivitamin contains the recommended amount of folate for most women. A higher dose of folate (5mg daily) is required for women who take medication for epilepsy, women with Type 1 Diabetes, women with a family history of neural tube defects and women with a BMI >30.
Iodine is an essential mineral obtained from the food we eat. Seafood is a great source of iodine, however the amount of iodine in other foods, such as vegetables and milk, varies depending on where it is grown or how it is produced. Over the past 10 years there has been a re-emergence of iodine deficiency in Australia and New Zealand, with nearly half the population thought to have inadequate iodine intakes. Iodine is an essential nutrient needed by humans in very small quantities. The thyroid, a small gland in the neck, uses iodine to produce thyroid hormones which are vital to ensuring the normal development of the brain and nervous system before birth in babies and young children. For this reason, it is very important that pregnant and breastfeeding women get enough iodine. Mild to moderate iodine deficiency can cause learning difficulties and affect physical development and hearing.
In 2009 the Australian Government mandated that all salt used in food manufacture (except organic bread) contain iodine. However, because pregnant and breastfeeding women have the greatest need for iodine, the National Health and Medical Research Council (NHMRC) recommends that all women who are pregnant, breastfeeding or considering pregnancy take an iodine supplement of 150 micrograms each day. Make sure your pregnancy multivitamin contains this amount of iodine.
Women with pre-existing thyroid conditions should seek advice from their endocrinologist before taking an iodine supplement.
Vegetarians and vegans should be supplemented with Vitamin B12 in pregnancy and lactation. The RDI of B12 in pregnancy is 2.6 mcg/day. The RDI of B12 during lactation is 2.8 mcg/day.
Studies of pregnant women attending antenatal clinics in Australia and New Zealand have found an increased frequency of Vitamin D deficiency in some communities. Women at increased risk of Vitamin D deficiency include (i) those with reduced sunlight skin exposure e.g. veiled women, (ii) those who use sunscreen on a regular basis, (iii) dark-skinned women, (iv) mothers of infants with rickets and (v) women with a BMI >30. In these circumstances, testing should be considered and supplementation instituted where needed. Low maternal serum levels of Vitamin D in pregnancy are associated with low neonatal Vitamin D serum levels.8-10 .Vitamin D deficiency in the neonate and the infant is associated with impaired skeletal development and an increased incidence of hypocalcaemic seizures. From the mother’s perspective Vitamin D deficiency is known to be an important risk factor for the development of osteoporosis in later life.
Suggestions for supplementation:
For pregnant women with levels 30–49 nmol/L, commence 1,000 IU (25μg)/day (eg. 1 x Ostelin daily)
Pregnant women with levels < 30 nmol/L should commence 2,000 IU (50μg)/day. Repeat the Vitamin D level at 28 weeks gestation Pregnant women with Vitamin D level above 50nmol/L should take 400 iu Vitamin D daily as part of a pregnancy multivitamin .
The iron demands of pregnancy and lactation are particularly pronounced due to the expanded red cell volume, blood loss around the time of delivery and the demands of the developing fetus and placenta. Iron supplementation will generally be recommended for women at particular risk of iron deficiency. This includes vegetarians and women with a multiple pregnancy. Women with iron deficiency anaemia, will need additional supplementation, with a specific iron supplement, containing at least 60mg of iron daily. All women should have their haemoglobin level checked at the first antenatal visit and again at approximately 28 weeks’ gestation and any anaemia investigated and treated. Routine iron supplementation is not recommended in every pregnancy.
The recommended dietary intake of calcium per day for pregnant women is 1300mg (ages 14-18 years) and 1000mg (19-50 years). If the woman avoids dairy in her usual diet (e.g. lactose intolerant) and does not consume alternative high calcium food (e.g. calcium enriched soya milk), calcium supplementation is recommended at 1000mg/day. A Cochrane Systematic review has reported a benefit of calcium supplementation, of at least 1000mg/day during pregnancy, in reducing the incidence of hypertensive disorders and preterm labour. The effect on pre-eclampsia was greater for women with low baseline calcium intake.
Omega 3 (Fish oil)
Omega-3 fatty acids are known to be critically important building blocks for the developing fetal brain and retina. Their essential source is dietary intake, principally vegetable oils and seafood. Seafood is the richest source of the most biologically active Omega-3 fatty acids, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA
Women whose dietary intake of Omega-3 fatty acids is low, for example those who eat very little seafood, should consider a dietary supplementation which may be obtained from fish oil and some commercially available pregnancy supplements.
The place of fish oil supplementation for pregnant women is a subject of ongoing research. While some studies have shown a benefit of dietary supplementation with fish oil during pregnancy with regard to improvement of neurodevelopmental outcome and reduction of pre-term labour, other studies have not. No conclusive evidence of benefit using fish oil supplements in pregnancy is yet confirmed and further meta-analysis and well powered, high quality trials are needed.
Some studies have shown a possible link between high levels of caffeine intake and miscarriage and impaired fetal growth. Caffeine is found in coffee, tea, cola, chocolate and certain energy drinks. It is advisable to limit caffeine consumption to less than 200mg per day – ie: 2 cups of ground coffee or 4 cups of medium-strength tea, hot chocolate or cola per day.
Fish & Mercury
Seafood is a great source of protein and omega-3 fatty acids, and should be eaten 2-3 times per week. However research has shown that some types of seafood – particularly large, predatory fish – may contain higher levels of mercury, a naturally occurring element found in air, water and food. Fish take up mercury from streams and oceans as they feed. Large, predatory fish often have higher levels of mercury as they eat smaller fish containing mercury.
Babies developing in the womb seem to be most vulnerable to the effects of mercury on their nervous systems and it may slow their development in the early years. Research is ongoing but pregnant women should be selective about the types and amounts of fish they eat during pregnancy. It is advisable to eat less shark, ray, swordfish, barramundi, gemfish, orange roughy, ling and southern bluefin tuna. Also limit tuna steaks to one portion per week, or two 140g cans per week (the smaller tuna used for canned tuna contains less mercury). There is no restriction needed on the amount of salmon (including canned salmon), prawns or shellfish that can be eaten.
Exercise during pregnancy is beneficial and to be encouraged. Most women can safely maintain their pre-pregnancy level of exercise, although they may tire more easily. 30 minutes of moderate exercise each day is recommended during pregnancy and women who were previously sedentary can safely commence a light to moderate exercise program under the guidance of their doctor. Women with complicated pregnancies or a serious medical condition, or those who exercise at the elite athlete level, may need to modify their program. As a general rule, contact sports are best avoided.
Numerous studies investigating the effects of exercise on pregnancy, the foetus, and the mother have been performed in the last ten years. In a normal healthy pregnancy, no study has found any negative effect of moderate intensity aerobic training on the development of the foetusor the outcome of pregnancy. In fact, it appears that the benefits of exercise during pregnancy clearly outweigh the potential risks.
If you are planning vigorous exercise during pregnancy please discuss your plans with your Obstetrician. Many women find swimming or just being in water helpful – particularly later in pregnancy. In addition there are a range of pregnancy-specific exercise programs available – e.g. Preggi Bellies, Aquamums, and specific Pilates and Yoga classes.
The average weight gain in pregnancy is 11.5 – 16 kg for a woman of normal weight. If you are underweight you should aim to gain more weight during your pregnancy and if you are overweight you should aim to gain less weight.