Pregnant women who take calcium supplements could have a significant effect on their offspring's blood pressure, suggests a new study.

Researchers investigating the effects of calcium supplementation during pregnancy on offspring at three months and two-years-old found a strong correlation with lower blood pressure.

The team from the Oregon Health & Science University in Portland, US, assigned pregnant women to either receive 2g of calcium or placebo daily from weeks 13 to 21 of gestation and continuing until delivery. Blood pressure was measured in 260 children and their mothers at three months and again in 57 of these children when aged two years old.

Systolic BP in the calcium-supplemented infants was 2.2mm Hg lower than in the placebo group. This positive effect appeared to increase with time, dropping to 4.8 mm Hg lower in the calcium supplemented group when tested at two-years-old. Diastolic BP was 3 mm Hg lower.

"The data on blood pressure in the children are in agreement with previous studies and argue strongly for additional research into the effects of prenatal calcium supplementation on blood pressure regulation in the offspring," concluded the researchers in this month's American Journal of Hypertension.

The study is likely to attract the attention of those supporting the significant impact of prenatal nutrition on long-term health of offspring.