A TINY NOTE ON FOLIC ACID IN PREGNANCY

WHAT IS FOLIC ACID?

Folic acid is the name given to the synthetic form of vitamin B9 called folate. While our body gets folate from natural foods; pharmaceutical Industries make folic acid as a supplement. So, vitamin B9, folate and folic acid are the same stuff.

WHAT ARE THE SOURCES OF FOLATE?

Natural sources of folate include dark green vegetables, fresh fruits, peanuts, whole grains, beans, sunflower seeds, eggs, seafood, liver, etc. The other (man-made) source is folic acid, a supplement.

WHY DO WE NEED FOLATE ESPECIALLY IN PREGNANCY?

Folate helps the body to build red blood cells and genetic materials (DNA and RNA). It also helps the body to metabolize protein and, most importantly, in the development of the brain and spinal cord in unborn babies.

WHAT DOES FOLIC HELP IN THE PROPER DEVELOPMENT OF THE BRAIN AND SPINAL CORD?

Here is a little embryology for you; remember that you need to understand life from the basics.

On the 16th day during the development of the embryo a flat plate of special cells develops and lies along the entire back of the embryo. This plate is called the neural plate.

Between day 16 and day 20, the two sides of the neural plate are lifted and folded towards the centre to meet each other, much like a baker forming a sausage roll with pasta.

By day 25 i.e. 4th week of pregnancy, the neural plate has completely folded itself into a kind of tube (of special cells) with sealed ends. This tube is called the neural tube, from which the brain and spinal cord will be formed.

While the upper end of the neural tube balloons out to form the brain, the rest of it remains slender as the spinal cord.

For proper development and closure of neural tube in the embryo, folate/folic acid is necessary. Since the amount available to a pregnant woman from natural sources is hardly enough, she’s advised to take at least 400 micrograms of folic acid supplement daily to prevent neural tube defects (NTDs).

WHEN SHOULD A PREGNANT WOMAN START TAKING FOLIC ACID

From the explanation above, the answer is simple. If she’s going to be pregnant today, the best time to start is yesterday. We have seen that the most critical period for best utility of folic acid in pregnancy is the first 14 weeks (called first trimester) and specifically in the first four weeks when the brain and spinal cord are formed.

NEURAL TUBE DEFECTS ARE CONSEQUENCES OF VIT B9 DEFICIENCY

In the absence of sufficient folate/folic acid in the first four weeks of pregnancy, the neural plate may not properly fold and close
to form the neural tube.

The implication of defective closure of the neural tube is that the brain might not form (this is called anencephaly), or the spinal cord may form a bulging mass which does not allow the backbone to close (this is called spinal bifida).

So, the two most common neural tube defects (NTDs) are spinal bifida and anencephaly. While a baby with spina bifida (i.e. divided spine) might live with hydrocephalus (water-filled brain), some neurological deficits and possibly some other defects, the anencephalic baby without brain and skull vault won’t survive at birth.

WHEN CAN DIAGNOSIS OF NEURAL TUBE DEFECTS BE MADE?

Diagnosis can be made in the womb by an ultrasound scan or magnetic resonance imaging (MRI). One of the first things that might prompt a doctor to request a check for a NTD is a pregnant tummy far bigger than it should be for the age of the pregnancy because of excessive waters (or amniotic fluid). This condition is called polyhydramnios. However, this is not to say that polyhydramnios is always caused by NTDs; it’s just a common manifestation of NTDs.

© Dr Dave Okorafor