Vitamin D for Pregnancy
Verdict: Published with Warning
Across 6 PubMed studies, the evidence for Vitamin D in Pregnancy grades Tier A — moderate evidence. Effective, but with safety or population caveats.
A 🔵 A Moderate Evidence Published with Warning
Why this grade7-layer evidence engine
⚖️
Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.70
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
A · Published with Warning
Confidence
86%
Highly consistent evidence
Evidence level
E1
Cochrane high-quality SR/MA
▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.702
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (1 篇 > 0 negative)
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status
PubMed studies (6)L2 · primary research & systematic reviews
Regimens of vitamin D supplementation for women during pregnancy
Finding: Across 30 trials (7,289 women), higher-dose vitamin D (>=601 IU/d) may reduce gestational diabetes (RR 0.54, 95% CI 0.34-0.86; moderate certainty) but made little or no difference to pre-eclampsia (RR 0.96, 95% CI 0.65-1.42), preterm birth (RR 1.25, 95% CI 0.92-1.69), or low birthweight (RR 0.90, 95% CI 0.66-1.24; low/very-low certainty).
View on PubMed Effects of vitamin D in pregnancy on maternal and offspring health-related outcomes: An umbrella review of systematic reviews and meta-analyses
Finding: Umbrella review of 16 SR/MAs (250,569 women) found vitamin D supplementation increases birthweight and reduces pre-eclampsia, miscarriage and fetal/neonatal mortality, and deficiency is associated with higher preterm birth, SGA/low-birthweight and GDM risk; authors suggest >400 IU/day, but underlying review quality was largely low (AMSTAR-2 critically low for most included reviews).
View on PubMed A systematic review and meta-analysis on the effect of vitamin D in preeclampsia and gestational diabetes mellitus in pregnancy
Finding: Across 24 studies (52,372 participants), vitamin D supplementation in RCTs reduced pre-eclampsia by 42% (OR 0.58, 95% CI 0.43-0.78) and GDM by 45% (OR 0.55, 95% CI 0.36-0.87), while in cohort studies deficiency raised GDM risk (OR 1.29, 95% CI 1.16-1.43) but was not significantly linked to pre-eclampsia (OR 1.67, 95% CI 0.92-3.01).
View on PubMed Effects of vitamin D supplementation on glucose metabolism and pregnancy outcomes in GDM: a systematic review and meta-analysis
Finding: Across 20 RCTs (1,737 women with GDM), vitamin D improved fasting glucose (SMD -1.01, p=0.0002), HOMA-IR (SMD -0.91, p=0.001) and insulin (SMD -0.64, p<0.0001), and reduced cesarean (RR 0.68), preterm birth (RR 0.28) and macrosomia (RR 0.34), though results are surrogate-heavy and warrant cautious interpretation given small trials.
View on PubMed Maternal gestational vitamin D supplementation and offspring bone health (MAVIDOS): a multicentre, double-blind, randomised placebo-controlled trial
Finding: In 1,134 women randomised to 1000 IU/day cholecalciferol vs placebo from 14 weeks' gestation, there was NO significant difference in neonatal whole-body BMC (61.6 g vs 60.5 g, p=0.21); a pre-specified secondary analysis suggested higher BMC only for winter-born infants.
View on PubMed Effect of Prenatal Supplementation With Vitamin D on Asthma or Recurrent Wheezing in Offspring by Age 3 Years: The VDAART Randomized Clinical Trial
Finding: In 881 pregnant women randomised to 4400 IU/day vs 400 IU/day vitamin D, offspring asthma/recurrent wheeze at age 3 was 24.3% vs 30.4% (HR 0.80, 95% CI 0.6-1.0; p=0.051), a 20% relative reduction that did NOT reach statistical significance.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Supportive
Vitamin D-3 is recognized as GRAS source↗
L4b EU EFSA
Supportive
cause and effect relationship has been established source↗
L4c UK NHS
Supportive
everyone should consider taking a daily vitamin D supplement during the autumn and winter source↗
L4d TW TFDA / 衛福部
Supportive
每日維生素D攝取量需達10微克 source↗
L4e WHO
Cautious
not recommended for all pregnant women source↗
L5a NIH Office of Dietary Supplements
Supportive
Vitamin D is a fat-soluble vitamin source↗
L5b Mayo Clinic
Supportive
You need 600 international units (IU) or 15 mcg of vitamin D a day during pregnancy. Good sources include fatty fish, such as salmon, and fortified milk and orange juice. Vitamin D works with calcium to help build your baby's bones and teeth. source↗
L5c Cleveland Clinic
Supportive
Vitamin D helps absorb the calcium that builds a fetus's bones and teeth. It also helps with eyesight and skin health. Sunlight is the best source of vitamin D, but you can also find it in fatty fish like salmon. You need at least 600 international units (IUs) of vitamin D a day. source↗
L5d Harvard Health
Supportive
The guidelines recommend supplements only in certain groups: Children (ages 1 to 18), adults 75 and older, pregnant women, and people with high-risk prediabetes. Adequate vitamin D during pregnancy also appears to reduce the chances of having a low-birthweight baby. source↗
L5e Specialty Society (condition-mapped)
Cautious
When vitamin D deficiency is identified during pregnancy, most experts agree that 1,000-2,000 international units per day of vitamin D is safe. Recommendations concerning routine vitamin D supplementation during pregnancy beyond that contained in a prenatal vitamin should await the completion of ongoing randomized clinical trials. At this time there is insufficient evidence to support a recomme… source↗