Pregnant women taking increased amounts of calcium during pregnancy may reduce the risk of hypertension, but no other positive benefits are proven, according to a new study.

While many obstetricians advise pregnant women to up calcium intake during pregnancy, there is no proof this increase helps the development of the baby or reduces the risk of any pregnancy related complications, aside from hypertension.

There is no debate that the diet of a pregnant woman impacts the health of the unborn fetus. Recent research has linked diet to increased risk of obesity and other health factors, but it does not appear that calcium plays as important a role as other nutritional factors. Calcium will not reduce the risk of premature labor, lower than average birth weight or maternal bone density.

While increasing calcium during pregnancy may reduce the risk of hypertension, it does not prevent or inhibit preeclampsia. Preeclampsia is one known cause of pregnancy hypertension. There is no known cause of preeclampsia and no cure, other than child birth. If preeclampsia occurs before the pregnancy reaches full-term, there is an increased risk of premature birth and potential side effects.

This report is a compilation of 21 studies with about 16,000 participants. Due to the diversity of the study population, the small increase in birth weight could not be directly associated with calcium intake.

The report was completed by the Cochrane Library. The library looks at a combination of medical studies and renders results based on those studies. Doctors fall on both sides of the Cochrane Library's findings.

Some doctors believe calcium does have an indirect effect on pre-term labor. If calcium reduces the risk of hypertension and hypertension during pregnancy increases the risk of pre-term labor, there is good enough reason to suggest increased calcium intake during pregnancy. However, other doctors feel the impact of calcium supplements could increase the risk of heart attack and stroke. One doctor noted that calcium supplementation causes a mineral imbalance in the body. This imbalance could cause artery damage.

Researchers note new, larger and more comprehensive studies are needed to make a definitive ruling on calcium supplementation during pregnancy.

Source: Buppasiri P, et al. Cochrane Database of Systemic Reviews. 2011.