During pregnancy, calcium and vitamin D are transported from the mother to the fetus, contributing to the mineralisation of the fetal skeleton and neonatal vitamin D status. The dietary requirements for calcium and vitamin D in non-pregnant adults have been extended to pregnancy, on the basis of insufficient evidence to support pregnancy-specific values⁽¹⁾. However, calcium and vitamin D intakes are low in Irish women⁽²⁾ and there is currently no recommendation for supplementation of these nutrients during pregnancy in Ireland. The aim of this study was to describe the habitual calcium and vitamin D intakes among pregnant women in Ireland using data collected from women participating in the DMAT randomised controlled trial (RCT) [Nutritional Requirements for Vitamin D in Pregnant Women (DMAT), NCT02506439].

Participants (n = 100) were healthy Caucasian women who were having a low-risk pregnancy and receiving antenatal care at the Cork University Maternity Hospital. Dietary vitamin D and calcium intakes were assessed at baseline (⩽18 weeks gestation) using a quantitative food frequency questionnaire⁽Reference Kiely, Collins and Lucey³⁾. Mean ± SD total calcium intake was 1227 ± 491 mg/d, and 26 % of women consumed calcium in supplemental form (dose range = 22–500 mg/d). Mean ± SD total vitamin D intake was 10·8 ± 5·3 µg/d. Sixty-eight percent of women reported taking a vitamin D-containing supplement (dose range = 2·1–10 µg/d).

Table 1. Sources of vitamin D and their contribution to total vitamin D intake

The prevalence of antenatal multivitamin use was high in this sample and was the major contributor to overall vitamin D intake. Among women not consuming a vitamin D-containing supplement, mean daily intakes were approximately half the current EAR (4·9 ± 3·4 µg/d). These findings highlight the current importance of nutritional supplements to meeting dietary requirements for vitamin D in pregnancy. These data will contribute to analysis of the dose response of 25(OH)D to total vitamin D intake in the DMAT RCT, which aims to inform vitamin D requirements during pregnancy and the neonatal period, and will report in full during winter 2016.