What is the standard folic acid indication for women with a previous child who had neural tube defects (NTD)?

For women who have previously delivered a child with neural tube defects (NTDs), the standard recommendation for folic acid supplementation is significantly higher than that for the general population. Specifically, a dose of 4 mg (4000 micrograms) of folic acid per day is advised. This higher dosage is aimed at reducing the risk of another affected pregnancy, as maternal folate levels are crucial in the early stages of fetal development, particularly in the formation of the neural tube.

The rationale behind this recommendation is based on evidence demonstrating that increased folic acid intake can considerably lower the recurrence risk of NTDs. Women with a prior history of NTDs are at a higher risk for having another affected child, and adequate folic acid supplementation is a key preventive strategy.

In contrast, the general population is typically recommended to take 0.4 to 1 mg of folic acid daily, which is considered sufficient for preventing NTDs in pregnancies without prior history. However, for those with a previous child affected by NTDs, the increased dose of 4 mg is essential for optimal protective effect.