Pre-eclampsia is a condition that can develop in the 2nd half of pregnancy. It is characterised by high blood pressure in the mother, along with protein in the urine. Late in pregnancy the condition can cause fitting, which can have serious (and even fatal) consequences for the mother and her baby.
I was interested to read about a recently-published study which tested the effect of calcium supplementation in a group of Indian (New Delhi, India) pregnant women . More than 500 women were randomised to received 2 g of calcium or placebo from week 12 to week 25 of their pregnancies. Those taking the calcium were 69 per cent less likely to suffer from pre-eclampsia. They were also 49 per cent less to give birth prematurely.
It is worth noting, I think, that the women in this study had generally low calcium intakes (an average of 313 mg per day). And therefore it is not known from this study whether the results will generally apply to women who have higher calcium intakes.
However, it is also worth taking this research in the context of other, similar research. In 2006, trials in which calcium had been used with the intention of preventing pre-eclampsia were assessed by a group of researchers from the Cochrane collaboration . Each of these trials employed at least 1 g of calcium each day and, again, typically the women studied ate diets relatively low in calcium.
Taken together, the results of12 trials (totalling more than 15,000 women) showed that calcium supplementation reduced risk of pre-eclampsia by more than half. In women with low calcium intake, risk reduction was 64 per cent. In contrast to the latest study, calcium supplementation had no statistically significant effect on the risk of pre-term birth.
The Cochrane review looked at other outcomes too, including risk of high blood pressure (reduced by 30 per cent in the women taking calcium), as well as risk of death of the mother or ‘serious morbidity’ (reduced by 20 per cent in the group taking the calcium).
It seems that this simple, cheap intervention may have considerable potential in the prevention of pre-eclampsia, particularly for women whose diets are generally low in calcium.
1. Kumar A, et al. Calcium supplementation for the prevention of pre-eclampsia. Int J Gynaecol Obstet. 2009;104(1):32-6.
2. Hofmeyr GJ, et al. Calcium supplementation during pregnancy for preventing hypertensive disorders and related problems. Cochrane Database Syst Rev. 2006 Jul 19;3:CD001059.