Supplements
folic acid decreases recurrent pregnancy loss
Part of: 🧪 Folate & L-methylfolate
📅 Last reviewed: 2026-07-15 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Population patterns (Observational)
How the studies fall
What the evidence shows
Folate/vitamin supplementation reduces miscarriage / recurrent pregnancy loss.
The evidence (6)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| cochrane-miscarriage-2016 2016 | meta-analysis | tested-null | high | Vitamin/folate supplementation did NOT reduce miscarriage (Cochrane). |
| Mao YY, Yang L, Li M, et al. 2020 · Nutrients | observational | supports | low | Cohort of 65,643 pregnancies (NFPHEP, China): periconceptional folic acid associated with LOWER spontaneous-abortion risk (aRR 0.52, 95% CI 0.48-0.56), with an earlier-initiation gradient. AUTHORS' OWN CAVEAT: the association 'might not thoroughly account for FA supplementation' and may partly reflect healthcare utilisation - i.e. confounding by engagement with care. Observational benefit sits directly against the Cochrane RCT null. |
| Xie M et al 2025 · study_type: meta-analysis | meta-analysis | mixed | low | Systematic review/meta-analysis of 11 RCTs (active folate vs folic acid) in women of childbearing age: active-folate supplementation associated with increased subsequent pregnancy rates (P=.0005) and decreased incidence of adverse pregnancy |
| Chen X et al 2026 · study_type: observational | observational | supports | moderate | Prospective cohort of 11,033 couples + 2862 unpaired mothers: each 100 ng/mL increase in maternal RBC folate associated with 8% lower spontaneous pregnancy loss risk (aRR 0.92, 0.85-0.98); paternal folate 19% lower (aRR 0.81); both parents |
| Hekmatdoost 2015 2015 · PLoS One | RCT | tested-null | moderate | 5-MTHF vs folic acid in recurrent miscarriage; outcome modulated by MTHFR genotype |
| Kjaergaard 2022 2022 · Eur J Clin Nutr | observational | contradicts | moderate | MR: genetically elevated homocysteine NOT causal for pregnancy loss |
Disagree, or know a study we missed?
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