(RxWiki News) Pregnant women are often told to take more calcium to benefit themselves and their babies, but the benefits of doing so have been unclear.
The connection between good prenatal nutrition and healthy newborns and new moms is quite clear. The effects of prenatal calcium supplements have recently been studied, and all that extra calcium could possibly be, by and large, a waste.
"Taking calcium megadoses while pregnant offers health advantages."
A review led by Pranom Buppasiri, M.D., of the department of obstetrics and gynecology at Khon Kaen University in Thailand, shows that calcium supplementation has no effect on preventing premature birth or low birth weight. The researchers also found that increased calcium intake has no effect on bone density in pregnant women.
One benefit, though, was evident: Calcium supplementation does help prevent preeclampsia, a dangerous condition marked by high blood pressure and protein in the urine that can lead to serious complications for the mother and her baby. The definitive treatment for preeclampsia is delivering the baby, which often results in premature babies that frequently weigh less than they should.
The review is not without controversy. Stephen Contag, M.D., with Sinai Hospital of Baltimore's Institute of Maternal Fetal Medicine, called the review confusing, pointing out that women who take extra calcium while pregnant might prevent premature birth because the extra calcium in their blood prevents high blood pressure, which can lead to preeclampsia and preterm delivery.
To counter Dr. Contag's position, John McDougall, M.D., a nutrition expert and medical director of the McDougall Program in Santa Rosa, California, cited a July 2010 study in the British Medical Journal to support his decision not to prescribe calcium supplements because they increase the risk of heart attacks and strokes.
Explains Dr. McDougall in a commentary regarding the July study, "Certainly, taking isolated concentrated minerals, such as calcium, creates physiological imbalances in the body. Immediately after consuming calcium supplements, the calcium in the blood increases. Thereafter, the body must adjust to this large burden of minerals. One of the adverse effects appears to be artery damage."
More than 16,000 women participated in the 21 studies included in the review. Dr. Buppasiri, though, notes that 21 studies are not enough to draw a definitive conclusion about calcium supplementation during pregnancy. He says that more high-quality studies are needed, especially studies of pregnant women living in areas where the typical diet is low in calcium.
The review by Dr. Buppasiri and his colleagues appears in the latest issue of The Cochrane Library, a publication of the Cochrane Collaboration, an international organization that evaluates medical research.