Table 1.

Characteristics of included studies

Study (ref)	Country	Target population	Baseline Calcium intake as Low (< 900 mg/day), Adequate (>900g/day), Not specified)	Dose of Supplementation (Cumulative dose)	Duration of supplementation	GRADE quality
Belizan et al 1991[37]	Argentina	Nulliparous pregnant women, < 20 weeks gestation. No comorbid	Low	2 g/day	< 20 weeks of pregnancy till delivery	High
Kumar et al 2009 [38]	India	Primigravida women with gestational age between 12-25 weeks	Low	2 g/day	12-25 weeks of pregnancy till delivery	High
L-Jaramillo et al. 1989[41]	Ecuador	Nulliparous pregnant women, < 24 weeks of gestation. No comorbid	Low	2 g/day	23 weeks of pregnancy till delivery	Moderate
L-Jaramillo et al. 1990[40]	Ecuador	Nulliparous pregnant women in 28-30 weeks of gestation with positive roll over test	Low	2 g/day	28-30 weeks of pregnancy till delivery	Moderate
L-Jaramillo et al.1997[39]	Ecuador	Teenage (< 17.5 years) Nulliparous pregnant women < 20 weeks gestation. No comorbids or addiction	Low	2 g/day	20 weeks of pregnancy till delivery	High
Niromanesh et al. 2001[42]	Turkey	28-32 weeks pregnant women with positive roll over test and with at least one risk factor for pre-eclampsia. No chronic medical condition	Not specified	2 g/day	28-32 weeks of pregnancy till delivery	High
Purwar et al. 1996[43]	India	Nulliparous pregnant women < 20 weeks of gestation. No cormorbid	Low	2 g/day	20 weeks of pregnancy till delivery	High
Villar et al. 2006 [44]	Multicenter trial (Argentina, Egypt, India, Peru, South Africa and Vietnam)	Primiparous women < 20 weeks of gestation. No comorbids	Low	1.5 g/day	From enrollment till delivery	High
Taherian et al. 2002[46]	Iran	Nulliparous pregnant women < 20 weeks of gestation. No comrbids	Low	500 mg/day	From enrollment till delivery	Moderate
Wanchu et al. 2001[45]	India	Nulliparous pregnant women < 20 weeks of gestation. No known comorbids	Low	2 g/day	From enrollment till delivery	Moderate