It is uncommon.
What is the natural source of folic acid?
Practically all foodstuffs contain folic acid. This includes grains (such as corn and rice) as well as vegetables. Unfortunately, folic acid is very susceptible to heat and is rapidly destroyed by cooking. Boiling vegetables for five minutes will destroy about 90 per cent of their folic acid content. A proper balance and preparation of food generally provides adequate folic acid, in normal circumstances.
The recommended daily dose of folic acid in such circumstances is 5 mg. A higher dose of 10 mg or thereabouts is occasionally recommended when the problem is particularly serious. This is uncommon. In any case, many of these women will be taking folic acid even before conception and it will be a matter of checking whether the dose needs to be adjusted.
Women who suffer from epilepsy and who are taking anticonvulsant medication are also strongly advised to take folic acid supplements preferably at a dose of 5 mg daily.
Multiple pregnancy is another indication for folic acid supplements, because of the increased demand and therefore an increased risk of deficiency.
If the mother was folic acid deficient before conception, the risk of neural tube defects - especially spina bifida - is increased.
There is irrefutable evidence that folic acid supplements taken in the period leading up to conception and in the days immediately after will reduce the risk of spina bifida quite considerably. It is particularly crucial for mothers who have had an affected baby in the past.
Other anomalies that have been associated with pre-conception folic acid deficiency include cleft lip ("hare-lip") and cleft palate.
Not the unborn baby. Even when the mother is deficient of folic acid, the placenta will actively transport folic acid to the fetus to meet its needs. However, since the stores are likely to be tenuous, the newborn is at risk of developing anaemia as a result of folic acid deficiency within a few weeks of birth.
Can folic acid deficiency lead to preterm labour?
Folic acid deficiency has not been linked with preterm labour or delivery.
This is a descriptive term used for the type of anaemia brought about by folic acid deficiency. The term "megaloblastic" is purely descriptive. It reflects the fact that in this type of anaemia, the blood-cells are larger than normal ("mega").
It is also important to stress that folic acid deficiency is not the only cause of megaloblastic anaemia. Deficiency of vitamin B12 will also cause this.