Cong 1995.

Methods	“Healthy antepartum cases were randomized and divided into 3 groups.”
Participants	Healthy primipara. Setting and dates of recruitment not stated (China)
Interventions	A: 120 mg calcium daily; B: 240 mg calcium daily; C: no calcium (D: 1 g calcium; E: 2 g calcium; E: no calcium: not included as trials with high risk of bias not included in high calcium dose review).
Outcomes	Biochemical studies; hypertension, pre‐eclampsia, birthweight, gestational age, method of delivery.
Notes	First period (low dose) April 1987 to June 1988 (groups A, B, C); second period (high dose) April 1989 to June 1990 (groups C, D, F). Similar results for groups A and B, which were combined in this meta‐analysis Source of funding: not stated. CoI: not stated.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	High risk	No placebo
Blinding of outcome assessment (detection bias) All outcomes	High risk	No placebo
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Loss to follow‐up not reported
Selective reporting (reporting bias)	Unclear risk	Limited information
Other bias	High risk	Very limited description of methods