Prepregnancy and early pregnancy calcium supplementation among women at high risk of pre-eclampsia: a multicentre, double-blind, randomised, placebo-controlled trial

Study answer

What this study found

Calcium supplementation started before conception and continued through 20 weeks' gestation did not significantly reduce recurrent pre-eclampsia overall. In pregnancies continuing to at least 20 weeks, pre-eclampsia occurred in 69/296 (23%) of the calcium group versus 82/283 (29%) of the placebo group, RR 0.80 (0.61-1.06), p=0.121; when expressed among all randomised women, the rates were 69/678 (10%) versus 82/677 (12%), RR 0.84 (0.62-1.14), p=0.258. A broader composite of pre-eclampsia or pregnancy loss showed a borderline reduction, 107/323 (33%) versus 126/310 (41%), RR 0.82 (0.66-1.00),…

Study & population

Multicentre, double-blind, randomised, placebo-controlled trial in parous women with a previous pregnancy complicated by pre-eclampsia or eclampsia who were planning another pregnancy.

Intervention

The active intervention was 500 mg elemental calcium daily as calcium carbonate, given as one chewable oral tablet from prepregnancy until 20 weeks' gestation.

Key limitation

The trial was powered to detect a large effect, so a smaller clinically relevant benefit cannot be excluded.

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Original abstract