Does folic acid use decrease the risk for spina bifida after in utero exposure to valproic acid?

Area of Science:

• Obstetrics and Gynecology
• Neurology
• Teratology

Background:

• Folic acid supplementation is recommended for women desiring pregnancy to prevent neural tube defects like spina bifida.
• Evidence for folic acid's protective effect is less established in pregnancies exposed to antiepileptic drugs, specifically valproic acid (VPA).

Purpose of the Study:

• To investigate the efficacy of folic acid in mitigating the risk of spina bifida in pregnancies exposed to valproic acid during the first trimester.

Main Methods:

• A case-control study utilized data from a population-based registry of congenital malformations.
• Spina bifida cases were compared against other malformed infants, excluding those with folic acid-sensitive malformations, to assess folic acid's effect.

Main Results:

• The odds ratio (OR) for correct folic acid use was 0.5 (95% CI: 0.3-0.7) in antiepileptic drug (AED)-unexposed pregnancies.
• In VPA-exposed pregnancies, the OR for folic acid use was 1.0 (95% CI: 0.1-7.6), indicating no statistically significant protective effect.

Conclusions:

• The study lacked sufficient power to definitively conclude whether folic acid is ineffective against spina bifida in VPA-exposed pregnancies.
• While folic acid showed a reduced risk in AED-unexposed pregnancies, its role in VPA-exposed pregnancies, particularly for higher-level lesions, requires further investigation.
• Further research is needed to determine optimal folic acid forms and dosages for women using VPA to prevent spina bifida.