Is folic acid (Vitamin B9) effective in treating cervical dysplasia?

Folic Acid for Cervical Dysplasia

Folic acid supplementation does not effectively treat established cervical dysplasia and is not recommended for this indication. The highest quality randomized controlled trial demonstrates no clinical benefit in altering the course of diagnosed cervical intraepithelial neoplasia (CIN).

Evidence Against Folic Acid Treatment

The most definitive evidence comes from a well-designed randomized controlled trial that directly addresses this question 1:

• 235 women with grade 1 or 2 CIN were randomized to receive either 10 mg folic acid daily or placebo for 6 months 1
• No significant differences were observed between supplemented and unsupplemented groups regarding:
  • Dysplasia status 1
  • Biopsy results 1
  • Prevalence of HPV-16 infection 1

This finding was replicated in a second study of 154 subjects with similar methodology, which also showed no benefit of folic acid supplementation on established cervical dysplasia after 6 months of treatment 2.

Important Distinction: Prevention vs. Treatment

The evidence suggests a critical temporal distinction 1, 3:

• Folate deficiency may play a role as a cocarcinogen during the initiation phase of cervical dysplasia 1
• Women with lower red blood cell folate levels (lower tertile) had higher prevalence of HPV-16 infection (37%) compared to those in the upper tertile (16%) 1
• However, once dysplasia is established, folic acid supplements do not alter disease progression 1, 2

Historical Context and Confounding Factors

One older study from 1982 suggested benefit in oral contraceptive users 3:

• Showed improvement in biopsy scores with 10 mg folic acid daily for 3 months 3
• However, this study had significant methodological limitations and the findings have not been replicated in more rigorous trials 1, 2
• The morphological features of megaloblastosis from folate deficiency can be misdiagnosed as cervical dysplasia, which may explain apparent "improvement" in some cases 3, 2

Clinical Recommendation

Do not prescribe folic acid as treatment for diagnosed cervical dysplasia. The evidence clearly demonstrates lack of efficacy for altering the course of established disease 1, 2. Standard management protocols for CIN should be followed instead.

Common Pitfall to Avoid

Do not confuse the well-established role of folic acid in preventing neural tube defects 4 with any therapeutic role in cervical dysplasia—these are entirely separate clinical entities with different evidence bases.