Folic Acid and Pregnancy

Posted: 19. May, 2011 0

Folic acid (also known as folate) is a B group vitamin. It was named after the Latin word for leaf, folia, as it was first discovered in spinach and is mainly found in green leafy vegetables. The body stores very little folic acid – it is probably the most widespread vitamin deficiency in developed countries.

Why You Need It during Pregnancy

Folate is needed for a wide number of body functions, including the:

• healthy production of new cells
• metabolism of sugars and proteins
• maintenance of healthy nerves.

When a cell divides in two, its genes are copied so that each daughter cell contains a full set of genetic material. Folic acid is essential for this process, so that if your levels of the vitamin are low, cells that are dividing become larger than normal and are more likely to contain abnormal chromosomes. As pregnancy is a time of rapid growth and division of cells, good supplies of folic acid are vital. In fact, folic acid is the only vitamin you need twice as much of during pregnancy than at any other time. Like vitamin B12, it is especially needed by cells that are dividing rapidly, such as those in your baby’s developing central nervous system.

Lack of folic acid during the first few weeks of pregnancy can trigger a type of congenital abnormality known as a neural tube defect. This is when your baby’s central nervous system (spinal cord and brain) starts developing – around 3 weeks after the egg has been fertilized:

• first, a long thickening forms where your baby’s spine will eventually develop
• the edges of this thickening grow upwards to form a U-shaped groove
• the walls of the groove start to fold over and fuse to form a tube which will develop into the baby’s brain and spinal cord groups of cells then grow in and around the tube which will eventually form the protective back bones (vertebrae).

If folic acid is in short supply, the cells forming the neural tube cannot grow and divide properly. The neural tube does not fuse fully along its length, so a gap is left at the top or bottom of the spine. This is known as a neural tube defect, examples of which include:

• spina bifida – literally meaning split spine - a distressing condition in which one or more of the bones in the back (vertebrae) fail to develop properly so the spinal cord and nerves are damaged due to lack of bony protection. Sometimes the membranes surrounding the spinal cord and even the spinal cord itself may be abnormal, too.
• some cases of hydrocephalus (a build-up of cerebrospinal fluid in the skull due to faulty development of drainage channels) – but probably only those cases associated with spina bifida.
• anencephaly – a rare condition in which most of the brain and the top of the skull fail to form.

Other birth defects which have been linked with lack of folic acid include cleft palate, hare lip and abnormalities of the limbs, heart, lungs and skeleton.

Sadly, at least two babies are conceived with a neural tube defect every day. If a man or woman has had one previous child suffering from a neural tube defect, or if either parent is affected him- or herself, the risk of having a baby with a neural tube defect is 10 times greater than normal. If a man or woman has had two affected children, the risk of a third baby with a neural tube defect is 20 times greater. It is reassuring to know that taking a folic acid supplement can reduce these risks by 75 per cent.

There is still some way to go before all women who are planning a baby or who are pregnant increase their intake of folic acid. A recent survey by the UK Health Education Authority showed that only 27 per cent of women were spontaneously aware of the importance of folic acid during pregnancy, although this was better than the 9 per cent who were aware the previous year.

Folic acid supplements may also help to protect against preeclampsia, which was recently found to be linked with high levels of the amino acid, homocysteine. Around one in 10 people inherits higher than normal blood levels of homocysteine. This can damage artery linings (including those in the placenta) and more than triples the risk of a heart attack in later life. One in 160,000 people has extremely high levels, with 30 times the risk of premature heart disease. Folic acid supplements (400 – 650 meg per day) can lower homocysteine levels to reduce the risk of pre-eclampsia in affected women (and, if continued after pregnancy, supplements also reduce their long-term risk of a heart attack). Folic acid supplements during pregnancy may decrease the risk of the offspring developing a brain tumour during childhood by over 60 per cent.

How Much You Need

If you are planning a baby, you should increase your intake of folic acid in three ways, by:

1. choosing foods which have been fortified with folic acid (including many breakfast cereals and some breads)
2. eating more folate-rich foods such as green leafy vegetables
3. taking a daily dietary supplement of 400 meg folic acid daily.

Ideally, you should start boosting your intake at least 3 months before trying for a baby, or certainly from the time you stop using contraception. Supplements should continue for at least the first 12 weeks of pregnancy and preferably throughout the whole 9 months. After the first 3 months, you can drop down to taking 200 meg folic acid if you wish.

If you have previously conceived a child with a neural tube defect, you should take a supplement containing at least 10 times more folic acid. Supplements containing 5 mg folic acid are available on prescription for this purpose.

Research suggests that after having a baby, it takes more than 6 months for a mother to return to her pre-pregnancy folic acid levels.

Good Dietary Sources

Folic acid is such an important vitamin for health that more and more foods are being fortified with it to boost everyone’s intake. These are now also easier to spot, thanks to the UK Health Education Authority’s new ‘flash’ scheme which leading manufacturers are adding to their packaging. Look out for flashes saying:

• contains folic acid – on foods that can provide at least one-sixth of your daily requirement
• with extra folic acid – on foods enriched to provide at least half your daily requirements.

When planning a pregnancy, you should aim to eat foods rich in folic acid as well as taking folic acid supplements.

Folic acid is mainly found in green leafy vegetables and fortified foods.

Good Sources of Folic Acid for Pregnant Women

• fortified foods such as cereals and breads
• green leafy vegetables such as spinach, broccoli, Brussels sprouts, kale, spring greens
• green beans, cooked black-eyed beans and baked beans
• cauliflower
• potatoes
• wholemeal or granary-style bread
• yeast extract -soya products
• kidney
• dairy products
• citrus fruit
• eggs
• yoghurt

Don’t boil your vegetables for too long. Eat them crisp – or even raw – as prolonged boiling destroys much of the folic acid present in the green leaves. Folic acid is also destroyed by prolonged contact with light and air, but can be protected by the antioxidant, vitamin C (as by squeezing lemon juice over your vegetables).

Potential Problems

There is no evidence that taking folic acid supplements in the amounts recommended for pregnancy are harmful.

If you have epilepsy, and are taking drugs to stop your fits, you should seek medical advice before trying for a baby. Some anticonvulsant drugs work by interfering with the way your body handles folic acid, so supplements can affect your treatment. It is best to seek specialist advice about which anti-epilepsy drugs are safe to take during pregnancy, and what level of folic acid supplementation you need.

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