Pre-eclampsiaExposure to sunlight

There are a number of papers in the literature reporting that risk of preeclampsia is highest for conception in summer and delivery in winter including for Hong Kong1, Norway2, South Africa3, the United States4 and the state of Vermont5. Winter is when serum 25(OH)D levels are lowest.

Page last edited: 03 May 2011


  1. Tam, W. H. Sahota, D. S. Lau, T. K. Li, C. Y. Fung, T. Y. Seasonal variation in pre-eclamptic rate and its association with the ambient temperature and humidity in early pregnancy. Gynecol Obstet Invest. 2008; 66 (1): 22-6.
  2. Magnu, P. Eskild, A. Seasonal variation in the occurrence of pre-eclampsia. BJOG. 2001 Nov; 108 (11): 1116-9.
  3. Immink, A. Scherjon, S. Wolterbeek, R. Steyn, D. W. Seasonal influence on the admittance of pre-eclampsia patients in Tygerberg Hospital. Acta Obstet Gynecol Scand. 2008; 87 (1): 36-42.
  4. Bodnar, L. M. Catov, J. M. Roberts, J. M. Racial/ethnic differences in the monthly variation of preeclampsia incidence. Am J Obstet Gynecol. 2007 Apr; 196 (4): 324 e1-5.
  5. Phillips, J. K. Bernstein, I. M. Mongeon, J. A. Badger, G. J. Seasonal variation in preeclampsia based on timing of conception. Obstet Gynecol. 2004 Nov; 104 (5 Pt 1): 1015-20.