No effect of calcium and vitamin D intake on maternal blood pressure in a healthy pregnant population.

OBJECTIVES

Clinical studies have reported an inverse relationship between calcium and vitamin D intake and hypertensive disorders of pregnancy (HDP). The aim of this study was to investigate if there was an association between calcium/vitamin D intake, and vitamin D (25OHD) status, and maternal blood pressure (BP), during pregnancy and at 5-year follow-up.

STUDY

DESIGN

This was an observational study of 415 women who participated in the ROLO (Randomised cOntrolled trial of LOw glycaemic index diet for the prevention of recurrence of macrosomia) study. Maternal BP measurements were taken during each trimester and at 5-year follow-up. Calcium and vitamin D intake were determined at each trimester and 25OHD was measured in early and late pregnancy.

RESULTS

Over two-thirds of the cohort were vitamin D sufficient (25OHD > 30 nmol/L) and had adequate calcium intake (>750 mg/day). There was no correlation between calcium intake or vitamin D intake and maternal BP in trimester 1 to 3 or at 5-year follow-up. Vitamin D status at 13 weeks' gestation negatively correlated with mean arterial pressure in trimester 1 (r = -0.152, p = 0.044). There was no correlation however between 25OHD at 28 weeks' gestation and BP at 28 or 34 weeks' gestation or 25OHD and BP at 5-year follow-up.

CONCLUSIONS

In a healthy population of women with adequate calcium and vitamin D intake, no clinically significant correlation existed between calcium and vitamin D and maternal BP.