Table 3.

Selected randomized placebo-controlled trials on vitamin D influence on PE risk.

Author	Aim of the Study	Size of Groups	Vit D Dose (IU) and Duration of Treatment	GA at the Entry to the Study	Main Outcome
Mirzakhani et al. 2016 [217]	PE risk	Vit D (SG) 408 CG 408	4400 daily 400 daily	10–18th week	PE incidence SG 8.08% CG 8.33%, NS RR 0.97 95% CI: 0.61–1.53
Rostami et al. 2018 [256]	Vit D status screening	Screened Vit D 800 Without Vit D 200 Non screened 900	50,000–300,000 weekly or monthly; 6–12 weeks	<14th week	Screening reduces PE risk by 60% RR 0.40 95% CI: 0.30–0.60
Karamali et al. 2015 [257]	PE risk	Vit D (SG) 30 CG 30 patients with high PE risk	50,000 every 2 weeks	20–32nd week	PE incidence SG 3.3% CG 10% p = 0.3
Sablok et al. 2015 [228]	Pregnancy complication risk	Vit D (SG) 120 CG 60	60,000–120,000 every 4 weeks	20–32nd week	PE incidence SG 11.1% CG 21.1% p = 0.08
Ali et al. 2019 [258]	PE risk	Vit D (SG) 83 CG 81	4000 daily	at 13th week up to 12th week after delivery	PE incidence SG 1.2% CG 7.4% p = 0.049

PE—preeclampsia; Vit D—vitamin D; SG—study group; CG—control group; GA—gestational age; P—statistical significance; RR—relative risk; CI—confidence interval.