A review of 12 studies carried out by the Cochrane Collaboration found that a 1.5g dose of calcium by mouth during the second half of pregnancy significantly reduced the risk of hypertension and pre-eclampsia for women in communities with low dietary calcium.
However, for women with adequate dietary calcium, the supplement only reduced hypertension by 10%, and there was no significant reduction in the reduction of pre-eclampsia.
The reviewers, led by Dr Hofmeyr, head of the department of obstretics and gynaecology at East London hospital complex in South Africa, concluded that calcium supplementation during pregnancy is a safe and a relatively inexpensive way to reduce blood pressure in women more likely to develop hypertension, as well as in women with low dietary calcium intake.
“The review is likely to convince health providers of the need to ensure that pregnant women have adequate calcium intake,” Dr Hofmeyr said.
Hypertensive disease occurs in approximately 12% to 22% of pregnancies and is directly responsible for 17.6% of maternal deaths in the US alone, according to the American college of obstetricians and gynecologists. Pre-eclampsia, affecting 2% to 3% of all pregnancies, occurs when a mother’s blood pressure rises to the hypertensive range, and excretion of protein in the urine becomes too high.