Calcium prevents preeclampsia and lowers maternal morbidity/mortality

Taking at least 1 g of supplemental calcium cuts in half the risk for preeclampsia and lowers the risk of maternal death or serious morbidity by about 20%, according to a systematic review of 12 studies including over 15,000 women.

As an accompanying editorial points out, we often overlook the important role calcium plays in the activity of muscle cells, which directly affects blood pressure and uterine activity. This is why we often prescribe calcium channel blockers.

The authors of the review calculated the overall relative risk for preeclampsia in women taking calcium supplementation to be 0.48. The beneficial effects were most pronounced in women at high risk (RR 0.22) and in women with a low baseline calcium intake (RR 0.36). In addition, the relative risk for maternal death or serious morbidity in women taking calcium supplementation was 0.80. There was no effect on the risk of preterm birth, stillbirth, or death before hospital discharge.

Hofmeyr GJ, Duley L, Atallah A. Dietary calcium supplementation for prevention of pre-eclampsia and related problems: a systematic review and commentary. BJOG. 2007;114:933-943.

Steer P. Editor's choice: calcium, magnesium, and pregnancy. BJOG. 2007;114(8):i-ii.

Commentary from Sharon Phelan, MD, Professor, Department of Obstetrics and Gynecology, University of New Mexico Health Science Center School of Medicine, Albuquerque, NM.

The issue of calcium supplementation during routine prenatal care continues to be debated. Supplementation is relatively easy, has a physiologic basis for it to work, and if it does decrease the occurrence of preeclampsia in high-risk women, it can be easily implemented.

Currently ob/gyns place much of their emphasis on weight gain, and only if that's well outside the recommendations do we pay attention to the quality of a patient's nutrition. And currently the only way to get nutritional counseling in pregnancy is if the patient is diabetic. Perhaps research like this will help increase clinicians' awareness of the value of nutritional intervention.