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Clin Endocrinol (Oxf). 2016 May;84(5):680-6. doi: 10.1111/cen.12989. Epub 2016 Feb 11.

The persistence of maternal vitamin D deficiency and insufficiency during pregnancy and lactation irrespective of season and supplementation.

Author information

1
Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto, ON, Canada.
2
Division of Endocrinology, University of Toronto, Toronto, ON, Canada.
3
Department of Nutritional Sciences, University of Toronto, Toronto, ON, Canada.
4
Keenan Research Centre for Biomedical Science of St. Michael's Hospital, Toronto, ON, Canada.
5
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
6
Division of Obstetrics and Gynecology, University of Toronto, Toronto, ON, Canada.
7
Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON, Canada.

Abstract

BACKGROUND:

Pregnancy and lactation comprise a critical window spanning all seasons during which maternal vitamin D status potentially may influence the long-term health of the newborn. Women typically receive calcium/vitamin D supplementation through antenatal vitamins, but there has been limited serial evaluation of maternal vitamin D status across this critical window.

DESIGN/PATIENTS/MEASUREMENTS:

In this prospective observational cohort study, 467 women in Toronto, Canada, underwent measurement of serum 25-hydroxy vitamin D (25-OH-D) at mean 29·7 ± 2·9 weeks' gestation, 3 months postpartum and 12 months postpartum, enabling serial assessment across 3 seasons. At each assessment, vitamin D status was classified as deficiency (25-OH-D<50 nmol/l), insufficiency (25-OH-D≥50 nmol/l and <75 nmol/l) or sufficiency (25-OH-D≥75 nmol/l).

RESULTS:

The prevalence rates of vitamin D deficiency and insufficiency were 31·5% and 35·1% in pregnancy, 33·4% and 35·3% at 3 months, and 35·6% and 33·8% at 12 months postpartum, respectively. These high rates remained stable over time (P = 0·49) despite declining usage of antenatal calcium/vitamin D supplementation from pregnancy to 3 months to 12 months postpartum (P < 0·001). Indeed, on mixed model analyses, vitamin D deficiency and insufficiency in pregnancy were independently associated with decrements in average 25-OH-D over time of 49·6 nmol/l and 26·4 nmol/l, respectively (both P < 0·001). In contrast, season of baseline assessment and use of calcium/vitamin D supplements were independently associated with changes in 25-OH-D in the range of 3-5 nmol/l (both P < 0·008).

CONCLUSIONS:

The persistence of vitamin D deficiency/insufficiency during pregnancy and lactation, irrespective of season and supplementation, supports the emerging concept that current vitamin D supplementation in antenatal care is likely inadequate.

PMID:
26641010
DOI:
10.1111/cen.12989
[Indexed for MEDLINE]

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