Seasonal impact in the frequency of isolated spina bifida

Prenat Diagn. 2013 Oct;33(10):1007-9. doi: 10.1002/pd.4175. Epub 2013 Jul 19.

Abstract

Objectives: To evaluate whether a relationship exists between season at conception and occurrence of isolated spina bifida (ISB).

Study design: All fetuses with prenatal diagnosis of ISB were analyzed according to date of conception. We compared the seasonal rates of conception between ISB fetuses and a control group consisting of a cohort of fetuses delivered during the same period from 1992 to 2009.

Results: In the control group, conceptions were equally distributed among the four seasons. Chi-square analysis showed a significantly higher rate of ISB conceptions in the fall compared with the control group (16/36, 44% vs. 12467/50533, 25%, Odds Ratio (OR) 2.44, 95% confidence interval 1.21-4.92). Not a single woman with a fetus affected by ISB took preconceptional supplement of folic acid.

Conclusions: Seasonality affects the frequency of ISB. We hypothesize that the seasonal differences may reflect dietary and climate changes with reduced intake of folic acid in the fall.

Publication types

  • Letter

MeSH terms

  • Case-Control Studies
  • Female
  • Fertilization / physiology*
  • Humans
  • Pregnancy
  • Prenatal Diagnosis
  • Prevalence
  • Risk Factors
  • Seasons*
  • Spinal Dysraphism / diagnosis
  • Spinal Dysraphism / epidemiology*
  • Spinal Dysraphism / etiology*