Pregnancies are helped 10 ways by Vitamin D - umbrella analysis
Vitamin D supplementation during pregnancy and maternal and neonatal outcomes: results from a quantitative umbrella meta-analysis
BMC Pregnancy and Childbirth April 2026
Background
This umbrella meta-analysis aimed to examine the effect of prenatal vitamin D supplementation on maternal and neonatal outcomes.
Methods
Scopus and PubMed were searched up to September 2024 to include relevant studies. The outcomes included gestational diabetes mellitus (GDM), preeclampsia, cesarean section, preterm delivery (PTD), low birth weight (LBW), small for gestational age (SGA), stillbirth, neonatal mortality, birth weight, birth length, and head circumference at birth. Standardized mean difference (SMD) and relative risk (RR) with their 95% confidence intervals (CI) were used as effect sizes to pool the data using a random effects model.
ResultsThirty-five studies with 188,370 participants were included. Vitamin D supplementation lowered the risk of
- GDM (RR = 0.68, 95%CI: 0.53 to 0.88),
- preeclampsia (RR = 0.62, 95%CI: 0.56 to 0.69),
- PTD (RR = 0.77, 95%CI: 0.65 to 0.90),
- LBW (RR = 0.67, 95%CI: 0.54 to 0.84),
- SGA (RR = 0.73, 95%CI: 0.63 to 0.85),
- stillbirth (RR = 0.77, 95%CI: 0.62 to 0.95), and
- neonatal mortality (RR = 0.58, 95%CI: 0.40 to 0.84), while also
- enhanced birth weight (SMD = 75.68, 95%CI: 48.99 to 102.36),
- birth length (SMD = 0.25, 95%CI: 0.18 to 0.33), and
- head circumference (SMD = 0.15, 95%CI: 0.06 to 0.23).
These effects were observed with lower doses of vitamin D ((< 50,000 IU/week), shorter intervention periods (< 14 weeks), and among older participants ((≥ 27 years). Moreover, vitamin D supplementation was linked to the reduced risk of cesarean deliveries in some subgroups.
ConclusionsPrenatal vitamin D supplementation may be associated with a lower risk of certain adverse maternal and neonatal outcomes and may improve birth anthropometric measurements.
Subset of results
Fewer columns, removed studies of low Quality
Summary: 35 meta-analyses, Risk reduction: 23% to 42% - on approx. 50,000 IU of Vitamin D biweekly (or 4,000 IU daily)
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shows body parts that are formed before the 20th week of pregnancy
Need to at least start with a loading dose ASAP @ 2 weeks to get many of the Vitamin D benefits
| Problem | Vit. D Reduces | Evidence |
| 0. Chance of not conceiving | 3.4 times | Observe |
| 1. Miscarriage | 2.5 times | Observe |
| 2. Pre-eclampsia | 3.6 times | RCT |
| 3. Gestational Diabetes | 3 times | RCT |
| 4. Good 2nd trimester sleep quality | 3.5 times | Observe |
| 5. Premature birth | 2 times | RCT |
| 6. C-section - unplanned | 1.6 times | Observe |
| Stillbirth - OMEGA-3 | 4 times | RCT - Omega-3 |
| 7. Depression AFTER pregnancy | 1.4 times | RCT |
| 8. Small for Gestational Age | 1.6 times | meta-analysis |
| 9. Infant height, weight, head size within normal limits | RCT | |
| 10. Childhood Wheezing | 1.3 times | RCT |
| 11. Additional child is Autistic | 4 times | Intervention |
| 12.Young adult Multiple Sclerosis | 1.9 times | Observe |
| 13. Preeclampsia in young adult | 3.5 times | RCT |
| 14. Good motor skills @ age 3 | 1.4 times | Observe |
| 15. Childhood Mite allergy | 5 times | RCT |
| 16. Childhood Respiratory Tract visits | 2.5 times | RCT |
RCT = Randomized Controlled Trial
- Clicking on a tag at the bottom of this page will show 19+ Pregnancy pages with many (>10) studies