Khan 2013.
| Methods | Described as prospective randomised clinical trial | |
| Participants | Setting: women attending the antenatal clinic of a tertiary care hospital in West Bengal, India (described as serving a population with low socio‐economic status). Dates of recruitment: May 2010–April 2011. Inclusion criteria: 272 women. Healthy nulliparous women (18‐30 years) with singleton pregnancy, with BP < 140/90 mmHg and no proteinuria at first antenatal visit before 20 weeks. |
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| Interventions | Experimental intervention: 127 women. High‐dose calcium supplements (2 g oral elemental calcium, 4 tablets daily) from 20 weeks’ gestation. Comparison intervention: 145 women. Low‐dose calcium (500 mg plus placebo, 1 active and 3 placebo tablets of similar appearance daily). |
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| Outcomes | (Prespecified outcomes were not clear; it was stated what was recorded at subsequent antenatal visits but it was not clear if these were study outcomes). Reported: eclampsia and pre‐eclampsia, preterm birth, gestational age at birth, birthweight, IUGR, stillbirth, mean systolic and mean BP (not clear when the reported values were measured). | |
| Notes | Funding: not stated. CoI: not stated. |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Reported using a computer‐generated randomisation table |
| Allocation concealment (selection bias) | Unclear risk | This was reported to be a placebo controlled trial but it was not clear staff were aware of allocation at the point of randomisation. |
| Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | Placebo was supplied so women may have been blind to which arm they were in. It was not clear whether staff were aware of the treatment group. |
| Blinding of outcome assessment (detection bias) All outcomes | Unclear risk | It was not clear if it was recorded in notes whether women were in the intervention or placebo groups. |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | 10/272 were lost to follow up. |
| Selective reporting (reporting bias) | Unclear risk | We had no trial protocol and it was not clear what the study outcomes were (much data that was collected were not reported). Several outcomes were not well defined (e.g. not clear when mean BP values were recorded). |
| Other bias | Unclear risk | No baseline characteristics reported |