Research
Obstetrics
Vitamin D status in early pregnancy and risk of preeclampsia

Presented as a poster at the 10th Interdisciplinary Graduate Student (M. Achkar) Research Symposium, McGill University, Montreal, Quebec, Canada, April 1-2, 2014; in oral format at the First Annual Canadian National Perinatal Research Meeting, Banff, Alberta, Canada, Feb. 12-15, 2014; and in poster format at the Réseau de Recherche en Santé Buccodentaire et Osseuse retreat, Magog, Quebec, Canada, Jan. 16-17, 2014.
https://doi.org/10.1016/j.ajog.2014.11.009Get rights and content

Objective

We sought to examine the association between maternal serum 25-hydroxyvitamin D (25[OH]D) concentration in early pregnancy and the subsequent diagnosis of preeclampsia (PE).

Study Design

This was a nested case-control study from 2 prospective Canadian cohorts conducted in Quebec City, Quebec, and Halifax, Nova Scotia, from 2002 through 2010. Participants were pregnant women (n = 169 cases with PE and 1975 controls). Maternal serum was drawn <20 weeks of gestation, and 25(OH)D measurement was performed. Cases were ascertained from medical records. Logistic regression analysis was used to estimate adjusted odds ratios with 95% confidence intervals.

Results

Women who developed PE had a significantly lower 25(OH)D concentration at a mean gestational age of 14 weeks compared with women in the control group (mean ± SD 25[OH]D 47.2 ± 17.7 vs 52.3 ± 17.2 nmol/L, P < .0001). Women with 25(OH)D <30 nmol/L compared to those with at least 50 nmol/L had a greater risk of developing PE (adjusted odds ratio, 2.23; 95% confidence interval, 1.29–3.83) after adjustment for prepregnancy body mass index, maternal age, smoking, parity, season and year of blood collection, gestational week at blood collection, and cohort site. Exploratory analysis with cubic splines demonstrated a dose-response relationship between maternal 25(OH)D and risk of PE, up to levels around 50 nmol/L, where the association appeared to plateau.

Conclusion

Maternal vitamin D deficiency early in pregnancy defined as 25(OH)D <30 nmol/L may be an independent risk factor for PE. The relevance of vitamin D supplementation for women of childbearing age should be explored as a strategy for reducing PE and for promoting a healthier pregnancy.

Section snippets

Cohort design, participant recruitment, and blood collection

This nested case-control study originated from separate Canadian cohort studies of pregnant women recruited in Halifax, Nova Scotia, and in Quebec City, Quebec. Blood samples were collected <20 weeks of gestation prior to diagnosis of PE.

In Halifax, Nova Scotia, pregnant women attending the blood collection services laboratory for routine prenatal blood screening were invited to participate <20 weeks of gestation, based on self-report and if they were planning on delivering at the Izaak Walton

Participants’ characteristics

Of the number of cohort participants (9220: 2036 from Halifax, Nova Scotia, and 7184 from Quebec City, Quebec), 169 (1.8%) developed PE. Table 1 presents the characteristics of the study population by case-control status. There were no significant differences between mothers who developed PE and mothers who did not develop PE in terms of age, marital status, education, family income, infant sex, smoking in pregnancy, caffeine consumption, physical activity, and living in an urban or rural area.

Comment

This nested case-control study aimed to determine the association between low vitamin D status in early pregnancy and the subsequent diagnosis of PE. Maternal vitamin D deficiency, defined as 25(OH)D <30 nmol/L, was associated with a doubled odds of PE compared to concentrations >50 nmol/L. This relationship was significant both before and after adjustment for factors known to be related to PE and/or vitamin D status including maternal age, nulliparity,28 season,10, 25 and prepregnancy BMI.14,

References (37)

  • M.E. Helewa et al.

    Report of the Canadian Hypertension Society Consensus Conference, 1: definitions, evaluation and classification of hypertensive disorders in pregnancy

    CMAJ

    (1997)
  • A. Benigni et al.

    Effect of low-dose aspirin on fetal and maternal generation of thromboxane by platelets in women at risk for pregnancy-induced hypertension

    N Engl J Med

    (1989)
  • M. Makrides et al.

    Marine oil, and other prostaglandin precursor, supplementation for pregnancy uncomplicated by pre-eclampsia or intrauterine growth restriction

    Cochrane Database Sys Rev

    (2006)
  • A.R. Rumbold et al.

    Vitamins C and E and the risks of preeclampsia and perinatal complications

    N Engl J Med

    (2006)
  • W.B. Grant et al.

    An estimate of the economic burden and premature deaths due to vitamin D deficiency in Canada

    Mol Nutr Food Res

    (2010)

  • Vitamin D supplementation: recommendations for Canadian mothers and infants

    Paediatr Child Health

    (2007)
  • Janz T, Pearson C. Vitamin D blood levels of Canadians. Statistics Canada. Catalogue no. 82-624-X. Available at:...

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    The authors acknowledge the Canadian Institute of Health Research for funding the study.

    The authors report no conflict of interest.

    Cite this article as: Achkar M, Dodds L, Giguère Y, et al. Vitamin D status in early pregnancy and risk of preeclampsia. Am J Obstet Gynecol 2015;212:511.e1-7.

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