Gestational calcium supplementation and blood pressure in the offspring.

Background: The current study examined the relationship between calcium supplementation during pregnancy and blood pressure (BP) in the mother and offspring at 3 months and at 2 years postpartum.

Methods: Nulliparous pregnant women were assigned to either receive 2 g of calcium or placebo daily beginning between weeks 13 to 21 of gestation and continuing until delivery. Blood pressure was measured in children and their mothers at 3 months (n = 260) and (n = 57) at 2 years postpartum. Systolic BP was measured in the infants using a sphygmomanometer with ultrasonic amplification. For the toddlers, three supine BP measurements were taken from the right arm using a Critikon automated sphygmomanometer just after measurement of left ventricular wall thickness.

Results: Systolic BP in the calcium-supplemented infants was 2.2 mm Hg lower than in the placebo group (P >.05). At 2 years of age, systolic BP was 4.8 mm Hg lower in the calcium supplemented group (P <.05), whereas diastolic BP was 3 mm Hg lower (P >.05). There was no difference in left ventricular mass index between groups, although there was a significant correlation between systolic BP and wall thickness (P <.05). Maternal BP was positively correlated with circulating 1,25(OH)(2)D3 (P <.001) but did not differ between calcium groups at 3 months postpartum.

Conclusions: The data on BP in the children are in agreement with previous studies and argue strongly for additional research into the effects of prenatal calcium supplementation on BP regulation in the offspring.