Almirante 1998.

Methods	“divided into two groups and followed up until delivery.”
Participants	430 pregnant women who were nulliparas, adolescents and elderly. Dates of recruitment not stated. Setting not stated, Phillipines
Interventions	Group B: 212 women received 500 mg elemental calcium from 16‐20 weeks till delivery. Group A: 210 women served as controls.
Outcomes	Pre‐eclampsia, preterm birth, admission to NICU
Notes	Abstract only
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not specified
Allocation concealment (selection bias)	Unclear risk	Not specified
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	No record of loss to follow‐up
Selective reporting (reporting bias)	Unclear risk	No information
Other bias	High risk	Abstract only, no details, no placebo