Vitamin D status and recurrent preterm birth: A nested case-control study in high-risk women

J. M. Thorp*, C. A. Camargo, P. L. McGee, M. Harper, M. A. Klebanoff, Y. Sorokin, M. W. Varner, R. J. Wapner, S. N. Caritis, J. D. Iams, M. W. Carpenter, A. M. Peaceman, B. M. Mercer, A. Sciscione, D. J. Rouse, S. M. Ramin, G. B. Anderson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


Objective To determine whether vitamin D status is associated with recurrent preterm birth, and any interactions between vitamin D levels and fish consumption. Design A nested case-control study, using data from a randomised trial of omega-3 fatty acid supplementation to prevent recurrent preterm birth. Setting Fourteen academic health centres in the USA. Population Women with prior spontaneous preterm birth. Methods In 131 cases (preterm delivery at <35 weeks of gestation) and 134 term controls, we measured serum 25-hydroxyvitamin D [25(OH)D] concentrations by liquid chromatography-tandem mass spectrometry (LC-MS) from samples collected at baseline (16-22 weeks of gestation). Logistic regression models controlled for study centre, maternal age, race/ethnicity, number of prior preterm deliveries, smoking status, body mass index, and treatment. Main outcome measures Recurrent preterm birth at <37 and <32 weeks of gestation. Results The median mid-gestation serum 25(OH)D concentration was 67 nmol/l, and 27% had concentrations of <50 nmol/l. Serum 25(OH)D concentration was not significantly associated with preterm birth (OR 1.33; 95% CI 0.48-3.70 for lowest versus highest quartiles). Likewise, comparing women with 25(OH)D concentrations of 50 nmol/l, or higher, with those with <50 nmol/l generated an odds ratio of 0.80 (95% CI 0.38-1.69). Contrary to our expectation, a negative correlation was observed between fish consumption and serum 25(OH)D concentration (-0.18, P < 0.01). Conclusions In a cohort of women with a prior preterm birth, vitamin D status at mid-pregnancy was not associated with recurrent preterm birth.

Original languageEnglish (US)
Pages (from-to)1617-1623
Number of pages7
JournalBJOG: An International Journal of Obstetrics and Gynaecology
Issue number13
StatePublished - Dec 2012


  • Perinatal nutrition
  • preterm birth
  • vitamin D

ASJC Scopus subject areas

  • Obstetrics and Gynecology


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