Eating for pregnancy

Eating for pregnancy

When it comes to pregnancy, it can often seem as though everyone is full of good intentions and advice — but with your nutritional needs changing, how do you know what to eat (and what to avoid) at every stage of the process? Nutritionist Debbie Iles investigates.


Nutrients you need

When you are preparing your body for pregnancy, optimal nutrition and body weight can have a positive effect on fertility. In fact, some nutrients, such as folate, are important even before becoming pregnant.


Folate supplementation — which has been proven to reduce the incidence of neural tube defects — should ideally start two to three months prior to conception. This is because neural tube closure occurs in the fourth week, which is often before a woman knows she is pregnant. Since bioavailability from food sources varies considerably, supplementation is always recommended before and up to the end of your twelfth week of pregnancy.


Getting enough iron before falling pregnant is important, as women who are already iron-deficient prior to conceiving can find it difficult to rebuild their iron stores once pregnant. Having good iron stores in the first trimester, more so than later in your pregnancy, may have the most impact in terms of a healthy pregnancy. Studies have shown that iron-deficiency anaemia has been linked to pre-term delivery and low-birthweight babies.


Zinc plays an important role in reproductive health for both men and women. Red meat, poultry and legumes all contain zinc.


Antioxidants are necessary for a healthy reproductive system. Bright- coloured fruits, vegetables and leafy greens are great sources of vitamins C and E, B vitamins and beta-carotene, as well as other micronutrients and antioxidants.

What to eat

When planning for a baby, the emphasis is on achieving and maintaining a healthy weight. Aim for a body mass index (BMI) between 18.5-25 (see our BMI calculator), or a waist-to-hip ratio (WHR) — your waist measurement divided by your hip measurement — of 0.7.

Being overweight or having a high WHR may reduce your chances of conceiving. On the other hand, being underweight can also adversely affect fertility.

There is also some evidence to suggest that the foods you eat could play a role in fertility.

Harvard researchers followed nearly 18,000 healthy women for eight years to identify key elements that may increase chances of conception. Diets rich in monounsaturated fats and polyunsaturated (‘healthy’) fats, plant-based proteins such as nuts and legumes, whole grains, low-GI carbohydrates and folate — all hallmarks of a healthy diet — may promote fertility. Trans-fats (found in commercially made chips, biscuits and other treats) are best avoided.

What to avoid

Avoid smoking and limit alcohol when trying to conceive. Some evidence suggests that as few as five standard drinks a week may impact on a woman’s fertility.

The jury is still out on whether caffeine avoidance is necessary, although a high intake may increase the risk of low-birthweight babies or miscarriage in some women. Consume no more than 200mg (milligrams) caffeine a day (about two small coffees or up to three cups of tea).

What about unplanned pregnancies?

It’s a good idea for all women of reproductive age to include folate in their diet, particularly since many pregnancies are unplanned. If your pregnancy is a surprise, however, don’t panic — we do get folate in food, but as soon as you find you are pregnant be sure to start the folate supplement.


Nutrients you need

The requirements for most nutrients increase during pregnancy — with folate, zinc, iron, iodine and vitamin B6 especially important.


Supplementation is recommended up to the end of your twelfth week of pregnancy, although requirements remain high throughout the pregnancy. Use a registered medicine available over-the-counter from pharmacies.


Requirements are highest in the third trimester, since this is when the baby acquires two-thirds of his or her zinc stores.


The recommended daily intake (RDI) for iron is highest at this time — maternal iron deficiency can increase the risk of pre-term deliveries and low-birthweight infants. Boost your iron absorption by eating vitamin C-rich foods in conjunction with iron (in meat, fish and some plant-based sources). Avoid caffeine at mealtimes.


This trace element is exceptionally important for pregnant women and growing children. Iodine deficiency in pregnancy increases the risk of damage to a child’s brain and central nervous system. Marine foods and iodised salt can be valuable contributors — but increasing salt intake is rarely recommended. Fortunately, bread-making flours, including those used to make gluten-free bread, are now fortified with iodine (the exceptions are organic and some yeast-free breads). Supplementation is recommended: use the registered 150mcg (microgram) iodine-only supplement available from pharmacies.

Vitamin B6

Increased blood volume during pregnancy is the major reason vitamin B6 requirements are higher. Deficiency has been linked with pre-eclampsia or hypertension in pregnancy, excessive vomiting, and it may also impact on infant brain development. Vitamin B6, however, is readily available in vegetables, fruits and meats, so a balanced diet should easily ensure an adequate intake.


Amazingly, your calcium requirements don’t increase as the body absorbs calcium much better during pregnancy. Many women, however, don’t meet the RDI for calcium (three to four serves of dairy) so include enough dairy in your diet.

Vitamin B12

This vitamin is found naturally only in animal foods. Fortified foods or supplements must be used by women on a vegan or vegetarian diet, and this is especially important during pregnancy. Low B12 is associated with neural tube defects at birth.

What to eat

While pregnant women generally need to consume more of most vitamins and minerals, the same cannot necessarily be said of food, making the old ‘eating for two’ idea incorrect!

Energy requirements vary significantly between women, depending on their level of activity, stage of pregnancy, body composition and pre-pregnancy BMI. Most women, however, only need an extra 1400kJ per day in the second trimester and 1900kJ in the third — which is no more than a banana, a small tub of yoghurt and a small handful of almonds. Ask your doctor for advice on your specific energy needs during pregnancy.

Pregnant women are encouraged to eat 150g fish twice a week, but to avoid exposing your unborn child to excessive mercury, choose fish such as sardines, salmon and herring — these fish pack a mean omega-3 punch but are low risk for mercury.

If you crave certain foods, there is usually no reason why you can’t indulge a little — but pregnancy isn’t an excuse to go overboard on treats! Contrary to popular belief, food cravings are not an indication of what your body needs. Choose nutrient-dense foods such as fresh and dried fruit, nuts, yoghurt and lean protein to counter cravings. Limit foods such as soft drinks, sweets and fried foods, which contain empty kilojoules.

Pregnancy is a time to make every mouthful count and nutrient-rich foods will benefit your baby and keep you healthy.

What to avoid

Doctors recommend avoiding nicotine and alcohol during pregnancy as both substances can freely cross the placenta and harm your unborn child.

Limit caffeine to 200mg a day, as more than this has been found to increase the risk of low-birthweight babies and miscarriage.

Listeria infection (caused by food-borne bacteria) is also a concern for pregnant women. While it may only cause mild illness in the mother, it can result in miscarriage, stillbirth or an ill premature baby. The good news is that high temperatures kill listeria. To avoid infection, fresh food should be stored below 4°C and cooked food should be heated to above 75°C before serving. It’s best, therefore, to avoid salad bars, soft cheeses, soft-serve ice cream and cold meats while pregnant.

Are supplements necessary?

In an ideal world, achieving optimal nutrition can be possible through diet alone — pregnant or not. However, pregnancy places exceptional demands on your body and it is not always possible for women to eat the right amounts of the right foods.

The Ministry of Health recommends that women planning a pregnancy, or who are in the early stages of pregnancy, access the low-cost folic acid and iodine tables from a pharmacy. These are even cheaper when on prescription.

Unless you have been given specific recommendations from your doctor following a blood test, it is not advisable to supplement with individual minerals such as calcium, iron or zinc as they tend to compete with each other for absorption and may cause a nutritional imbalance.

To cope with morning sickness

  • Eat small frequent meals throughout the day.
  • Avoid offensive odours and get some fresh air.
  • Take a break from cooking if you can and make sure household bins are emptied daily.
  • Drink enough fluids.
  • Eat high-carbohydrate snacks, such as crackers, and sip on chilled drinks.

While a healthy diet is important, it’s more important to eat what you can keep down in the first few weeks. Be sure to take your folate and iodine supplements as recommended. Take them with food and/or at a time when you feel less ill. If vomiting persists beyond 14 weeks, see your doctor.


Nutrients you need

Breastfeeding, while undoubtedly the gold standard of infant nutrition, doesn’t always come easily. If you are having difficulty breastfeeding, talk to a lactation consultant or your doctor.

While breastfeeding, certain nutrients, energy and fluids will be in high demand — much more so than during pregnancy.


Zinc requirements are highest during this phase, at 12mg a day.


Iron is one of the few nutrients for which requirements lessen after pregnancy, particularly in breastfeeding mothers. Most women don’t begin ovulating immediately if they are breastfeeding, which means you retain the iron that would normally be lost through menstruation. Unless you were anaemic during pregnancy, or lost a lot of blood and have been advised to take supplements, you should be able to get enough iron from your diet.


A new mother’s iodine requirements are still very high as breast milk needs to contain an adequate iodine content to support your infant’s growing brain. It’s recommended you continue with the 150mcg iodine supplement until you have stopped breastfeeding.

What to eat

Exclusively breastfeeding an infant for around the first six months uses a lot of energy. Mothers need about an extra 2000-2100kJ a day. This is equivalent to about five extra slices of bread a day.

For the second six months, milk production is less, but energy needs are the same as body fat has reduced and is no longer available as an energy source.

You can keep your energy intake up with healthy, low-GI snacks, fruit and low-fat dairy foods. Choose nutrient-dense foods and aim for as much variety as possible since there is evidence to suggest that food flavours do enter breast milk. This may make your baby more accepting of a wide variety of foods when they start eating solids.

Drinking enough water is also important for breastfeeding women, although it doesn’t increase milk production. A good guide is to drink a glass at each meal and again with each breastfeed.

What to avoid

Whatever the mother consumes is excreted in her breast milk. This applies to nicotine, caffeine, alcohol and other drugs. Care also needs to be taken with prescription and over-the-counter medications so always advise the pharmacist if you are breastfeeding.

Alcohol is best avoided for at least four to six weeks after birth since breastfeeding can be unpredictably spaced at this time. It takes most women about two hours to clear one standard alcoholic drink from their bloodstream and their breast milk. You may want to plan the occasional drink with this in mind, or express first if you expect to drink more.

A cup of coffee or tea is fine when breastfeeding. However, keep your intake moderate (no more than 200mg a day), as it takes babies a lot longer to clear the caffeine from their blood.

In general, there is no need to avoid any particular foods, spices or potential allergens when breastfeeding. A minority of infants may suffer a food allergy or intolerance in response to food compounds in the mother’s breast milk, but it is important to remember that this is not the general rule. Address breastfeeding technique as the first port of call with unsettled newborns rather than food elimination. However, if your baby reacts strongly during or after breastfeeding, contact your doctor.

Additionally, no specific food has been shown to cause colic, so eat what you usually eat and aim for a wide variety of foods.

RDI* for nutrients at different stages of pregnancy

Nutrient: Folate

Found in: Bread, fortified cereals, green leafy vegetables, legumes, citrus fruit, berries

  • Pre-conception (RDI): 600mcg/day
  • Pregnancy (RDI): 600mcg/day
  • Breastfeeding (RDI): 500mcg/day

Do I need to supplement? Yes. Start two to three months before you plan to conceive and continue to the end of your twelfth week of pregnancy. Use the registered medicine available at pharmacies.

Nutrient: Iodine

Found in: Bread, iodised salt, seafood, eggs and dairy (amounts vary)

  • Pregnancy (RDI): 150mcg/day
  • Pre-conception (RDI): 220mcg/day
  • Breastfeeding (RDI): 270mcg/day

Do I need to supplement? Yes. Once pregnant, use the 150mcg iodine-only tablet available on prescription or over the counter at pharmacies.

Nutrient: Zinc

Found in: Red meat, fish, poultry, cereals, dairy, nuts, legumes

  • Pre-conception (RDI): 8mg/day
  • Pregnancy (RDI): 11mg/day
  • Breastfeeding (RDI): 12mg/day

Do I need to supplement? No.

Nutrient: Iron

Found in: Red meat, fish, poultry, wholegrain cereals, legumes, leafy greens

  • Pre-conception (RDI): 18mg/day
  • Pregnancy (RDI): 27mg/day
  • Breastfeeding (RDI): 9mg/day

Do I need to supplement? Not unless your doctor recommends it.

Nutrient: Vitamin B6

Found in: Meats, breakfast cereals, vegetables, fruit

  • Pre-conception (RDI): 1.3mg/day
  • Pregnancy (RDI): 1.9mg/day
  • Breastfeeding (RDI): 2.0mg/day

Do I need to supplement? No.

*RDI: Recommended Dietary Intake

Losing the baby weight… sensibly

New mums have a tough enough job without having to worry about unrealistic weight-loss expectations. After your baby is born, most weight-loss usually occurs in the first three months. After this, it typically begins to slow. It is important not to embark on any drastic diets, especially in the first six months after birth. Your focus should be on eating a healthy, balanced diet.

  • Include low-GI carbohydrates at each meal and snack to keep your energy levels up and blood glucose stable. Grainy breads, legumes, kumara, fruit and low-fat yoghurt are all good options.
  • Plan healthy snacks rather than mindlessly picking at food. Prepare portions of dried fruit and nuts, keep small tubs of low-fat yoghurt on hand and keep plenty of fruit in the fruit bowl.
  • Try to cut out any midnight munchies — just because your baby needs a midnight feed doesn’t mean you do, too! Keep a bottle of water and an apple close by. If you are not hungry enough to eat that apple, then you certainly don’t need any bread, biscuits or chocolate!
  • Consider getting your fresh produce delivered. Having a big box of fresh vegetables and fruit arrive on your doorstep will help you cut back on unhealthy impulse buys, save you time and energy, and encourage healthy eating.
  • Keep portion sizes appropriate. A palm-sized portion of lean meat and a fist-sized portion of carbohydrate is a good guide for meals. There are no limits on salads and non-starchy vegetables so go to town on these.

It is important to remember it took nine months to gain the baby weight, and it will likely take at least that long to return to your previous shape. Whatever you do, avoid extreme kilojoule restriction and try to return to some light exercise as soon as you feel ready.

Author: Debbie Iles

Healthy Food Guide

First published: Jan 2012

2017-04-03 16:55:46

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