Study	Reason for exclusion
Almirante 1998	This trial was reported in abstract form only. We emailed the authors for further information at the last publication of the review (2011) and have had no reply. The study has been excluded for insufficient information.
Asemi 2012	The intervention was not relevant. The intervention was a combination of calcium and vitamin D supplementation. The study population was at risk for pre‐eclampsia. The intervention took place in the third trimester. For these reasons the trial was excluded.
Chames 2002	This trial was reported in abstract form only. We emailed the authors for further information at the last publication of the review (2011) and have had no reply. The study has been excluded for insufficient information.
Diogenes 2013	The intervention was not relevant. The intervention for this trial was a combination of calcium and vitamin D.
Duggin 1974	The outcomes were not relevant and allocation to groups was not random. 7 primiparas (aged 16‐19 years) who were at 32‐36 weeks' gestation were included. The participants were divided into control participants (patient 1‐4) and supplemented participants (patients 5‐7) to measure metabolic balance.
Felix 1991	There was no random allocation to groups in this trial (women allocated to groups in sequence). The aim of the study was to examine the hypotensive effects of calcium in Andean women.
Galimberti 2001	This trial was reported in abstract form only. We emailed the authors for further information at the last publication of the review (2011) and have had no reply. The study has been excluded for insufficient information.
Hammar 1981	The participants were not appropriate. This study was aimed to determine the effect of calcium treatment in pregnant women who suffered from leg cramps; 42 pregnant women who suffered from leg cramps with gestational age 21‐38 weeks were included.
Janakiraman 2003	This was a cross‐over study examining bone resorption among pregnant women during received calcium supplementation. 32 pregnant women gestational age 25‐35 weeks participated in the study for 20 days. Each women received 1200 mg calcium supplement for 10 days and multivitamin without calcium for 10 days. N‐telopeptides of type I collagen (NTX), a biomarker of bone resorption were measured.
Kalkwarf 1997	The intervention was not appropriate. The study aimed to examine the effect of calcium supplementation on bone density in postpartum period. The randomised, placebo‐controlled trial of 1 g calcium supplementation was conducted in 97 lactating and 99 non‐lactating women a mean 16 ± 2 days postpartum (the study of lactation). The other trial (the study of weaning) 95 lactating women who weaned their infants in 2 months after enrolment and 92 non‐lactating women were enrolled 5.6 ± 0.8 months postpartum.
Kent 1995	The participants were not appropriate. This was a study focusing on the postpartum period and women were not randomised to receive calcium until 36 weeks' gestation. This trial aimed to study the effect of an oral calcium supplement on regional bone loss in normal lactation women. 79 pregnant women at gestational age 36 weeks were randomised to received placebo or 500 mg twice daily of calcium through to 24 weeks' lactation.
Liu 2011	The intervention was not appropriate. The participants were provided calcium supplementation until 6 weeks postpartum and measured bone mineral density post‐treatment.
Lopez‐Jaramillo 1990	The participants were not appropriate.The study aimed to examine the effect of calcium supplementation on risk of PIH in pregnant women who had a positive roll‐over test.
Mahomed 2000	The participants were not appropriate. The study aimed to examine the effect of calcium supplementation on risk of PIH and preterm labour in twin pregnancy.
Mazurkevich 2013	This intervention was not relevant. The intervention in this study was a combination of calcium carbonate and cholecalciferol.
Mukherjee 1997	The participants were not appropriate. The study aimed to examine the effect of calcium supplementation in reducing leg cramps in homogeneous Chinese population. All pregnant women who suffered from leg cramps during January 1994 and May 1995 were enrolled to received either calcium gluconate 600 mg twice daily or 2 multivitamin tablets twice daily.
Odendaal 1974	The participants were not appropriate. Calcium was supplemented only when participants suffered from leg cramps, which not relevant to the objective of the review.
Prentice 1995	This study did not examine calcium supplementation amongst pregnant women. 60 Gambian mothers consuming a low‐calcium were randomised to receive calcium supplement or placebo from 10 days to 78 weeks postpartum.
Qui 1999	The intervention was not relevant. Calcium was supplemented from 20 weeks' gestation to postpartum 45 days.
Robinson 1947	The intervention was not appropriate. Calcium was given to treat women with leg cramps, which was not relevant to the objective of the review.

g: grams
 PIH: pregnancy‐induced hypertension