Are calcium supplements important during pregnancy?

Kathleen Blanchard's picture
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In an investigation, researchers find no benefit for pregnant moms or their babies from taking calcium supplements. Until now, the role of supplementing with calcium during pregnancy has been unclear.

In a study review, researchers found calcium supplements during pregnancy might help prevent high blood pressure that leads to preeclampsia, but the effect is indirect and confusing.

High blood pressure and protein in the urine are symptoms of the condition that can lead to complications for mother and baby.

Preeclampsia is linked to lower birth weight and premature birth. Treatment of preeclampsia is involves delivering the baby.

According to Stephen Contag, MD, a perinatalogist at Sinai Hospital of Baltimore's Institute of Maternal Fetal Medicine, the finding that calcium supplementation during pregnancy might keep blood pressure lower, preventing preeclampsia is confusing

“There is an inherent confounding effect between the two interventions in that whenever maternal hypertensive disease is prevented, preterm labor is less likely to occur.

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In other words, calcium supplementation might prevent preterm labor indirectly by preventing high blood pressure. The definitive treatment for pregnancy related hypertensive disease is delivery, which often occurs preterm depending on the severity and timing of onset.”

For the current study, published in the Cochrane Review, led by Pranom Buppasiri, MD, of the department of obstetrics and gynecology at Khon Kaen University in Thailand, researchers reviewed 21 studies that included 16,000 women.

The review found calcium supplements had no benefit for preventing preterm birth, low infant birth weight. The supplements were also not found to help with bone density.

John McDougall, MD, an internist, nutrition expert and medical director of the McDougall Program in Santa Rosa, California, says he doesn’t prescribe calcium supplements for pregnant women. A July 2010 study in the British Medical Journal (BMJ) suggests supplements increase the risk of heart attacks and strokes because they damage the arteries.

McDougall commented on the BMJ study, saying calcium supplements can cause a physiologic imbalance in the body from increased calcium blood levels. When the body adjusts, it negatively affects arterial health.

Though the review found no benefit for calcium supplements during pregnancy, Buppasiri says more studies are needed to address the value of supplements for women with low intake of calcium.

Buppasiri P, et al.
"Calcium Supplementation (other than for preventing or treating hypertension) for improving pregnancy and infant outcomes"
Cochrane Database of Systematic Reviews 2011, Issue 10

Image credit: Morguefile

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Comments

The questions about calcium supplements are still coming, and yet so few answers! I was especially interested to see Dr. McDougall's comment about calcium...I remember interviewing him many years ago on nutrition.
They're still looking at this for sure Deborah. For now, I've stopped taking them, focusing on food sources.
Agree Deborah Mitchell, I find DR. McDougall highly respected within this area!