Table 3.
Randomized Controlled Trials of vitamin D supplementation in pregnancy
| Place of study | No. of participants | Intervention | Vit D assay method | Duration of intervention | Outcomes | Study authors | Quality of evidence (GRADE system) |
|---|---|---|---|---|---|---|---|
| Iran | 50 | Placebo Calcium 1000 mg/day + Vit D3 50,000 U on day 1 and 21 |
ELISA | 6 weeks | Metabolic profile of women with GDM | Asemi et al, 2013 | High |
| Australia | 209 | LD vit D3 400 U/day HD vit D3 5,000 U/day |
CLIA | till delivery | Primary: GDM Secondary: maternal and neonatal outcomes |
Yap et al, 2014 | High |
| Iran | 500 | LD vit D 400 U/day HD vit D 50,000 U/day |
- | till delivery | GDM, GHTN, pre- eclampsia, preterm, LBW. | Mojibian et al, 2015 | High |
| Pakistan | 193 | FeS04 200mg + Calcium 600mg/day + Vit D3 4,000 U/day | CLIA | 20 weeks to delivery | Pregnancy outcomes (GDM, GHTN, preterm labor, SGA, B wt, length, HC, Apgar at 1 and 5 min) | Hossain et al, 2014 | High |
| India | 180 | No intervention Vit D3 120,000 IU at 20, 24, 28 and 32 weeks |
ELISA | Preterm, pre- eclampsia, GDM, LBW and Apgar scores at 1 and 5 minutes | Sablok et al, 2015 | High | |
| Iran | 60 | Placebo Calcium 1000mg/day + vit D3 50,000 IU every 2 weeks |
ELISA | 12 weeks | Metabolic profiles in women at risk of pre- eclampsia | Samimi et al, 2015 | High |
| Iran | 46 | Placebo MM 800mg Ca+ 200mg Mg+ 8mg Zn + Vit D3 400 IU |
ELISA | 9 weeks | Outcomes in Pre- eclampsia patients | Asemi et al, 2015 | High |
| Iran | 60 | Placebo Vit D3 50,000 IU every 2 wks |
ELISA | 12 weeks | Metabolic profile and outcomes in pre-eclampsia patients | Karamali et al, 2015 | High |
| US | 440 | Placebo+ MV with Vit D 400 IU/day Vit D +MV with Vit D 4400 IU/day |
CLIA, LC-MS | till delivery | Asthma and recurrent wheezing in offspring | Litonjua et al, 2016 | High |
| Japan | 164 | Placebo Vit D3 800 IU/day |
6 weeks | Allergies like infantile eczema, atopic dermatitis, food allergy and wheeze | Norizoe et al, 2014 | High | |
| Iran | 130 | MVI + Ca 400 IU/day MVI+ Ca 400 IU/day + Vit D3 50,000 IU/ week |
ELISA | 8 weeks | Fetal growth (length, HC, weight) | Hashemipour et al, 2013 | Moderate |
Abbreviations used: Vit D (vitamin D), MVI (Multivitamin Injection), ELISA (Enzyme Linked Immune sorbent Assay), CLIA (Chemiluminescent Immunoassay), LC-MS/MS (Liquid Chromatography tandem Mass Spectrometry), GDM (gestational diabetes mellitus), GHTN (Gestational Hypertension), SGA (small for gestational age), LBW (low birth weight), HC (Head circumference),