Comment: The quality of evidence is downgraded by imprecise results (few patients and few outcome events).
A Cochrane review [Abstract] 1 included 10 studies. In this updated review, we added one new study with no relevant data and, following the trustworthiness assessment, removed data from 21 studies from the existing analyses.
Supplementation with vitamin D alone vs placebo/no intervention:Supplementation with vitamin D alone during pregnancy did not significantly reduce the risk of pre-eclampsia, gestational diabetes, low birthweight (less than 2500 g), and severe postpartum haemorrhage (table T1).
Supplementation with vitamin D plus calcium vs placebo/no intervention:The effect of the intervention was uncertain.
| Outcome | Relative effect (95% CI) | Risk with placebo/control | Risk with intervention - vitamin D supplementation (95% CI) | №of participants (studies) Certainty of the evidence |
|---|---|---|---|---|
| Pre-eclampsia | RR 0.53 (0.21 to 1.33 | 140 per 1000 | 74 per 1000 (29 to 187) | 165 (1) Very low |
| Gestational diabetes | RR 0.53 (0.03 to 8.28) | 18 per 1000 | 9 per 1000 (1 to 145) | 165 (1) Very low |
| Low birthweight (less than 2500 g) | RR 0.69(0.44 to 1.08) | 220 per 1000 | 151 per 1000 (97 to 237) | 371(3) Low |
| Preterm birth (less than 37 weeks' gestation) | RR 0.76 (0.25 to 2.33) | 42 per 1000 | 32 per 1000 (10 to 97) | 1368(3) Very low |
| Maternal adverse events: severe postpartum haemorrhage | RR 0.68 (0.51 to 0.91) | 169 per 1000 | 115 per 1000 (86 to 154) | 1134 (1) Low |
Another Cochrane review 2 included 30 trials involving 7289 women.
601 IU/d or more versus 600 IU/d or less of vitamin D alone or with any other nutrient (19 trials; n=5 214)Supplementation with 601 IU/d or more of vitamin D during pregnancy may make little or no difference to the risk of pre-eclampsia (RR 0.96, 95% CI 0.65 to 1.42; 5 trials; n=1553), may reduce the risk of gestational diabetes (RR 0.54, 95% CI 0.34 to 0.86; 5 trials; n=1846), may make little or no difference to the risk of preterm birth (RR 1.25, 95% CI 0.92 to 1.69; 4 trials; n=2294); and may make little or no difference to the risk of low birthweight (RR 0.90, 95% CI 0.66 to 1.24; 4 trials; n=1550) compared to women receiving 600 IU/d or less.
4000 IU or more versus 3999 IU or less of vitamin D alone (15 trials; n=4763)Supplementation with 4000 IU/d or more of vitamin D during pregnancy may make little or no difference to the risk of: pre-eclampsia (RR 0.87, 95% CI 0.62 to 1.22; 4 trials, n=1903); gestational diabetes (RR 0.89, 95% CI 0.56 to 1.42; 5 trials, n=2276); preterm birth (RR 0.85, 95% CI 0.64 to 1.12; 6 trials, n=2948); and low birthweight (RR 0.92, 95% CI 0.49 to 1.70; 2 trials; n=1099) compared to women receiving 3999 IU/d or less.Adverse events (such as hypercalcaemia, hypocalcaemia, hypercalciuria, and hypovitaminosis D) were reported differently in most trials; however, in general, there was little to no side effects reported or similar cases between groups.
Date of latest search:2024-11-22
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