title: Seasonal variation in gestational blood pressure.
abstract: OBJECTIVE
  To assess seasonal variability in antenatal blood pressure (BP).
  
  
  METHODS
  We studied 1919 pregnant women who contributed 21,119 antenatal BP measurements.
  
  
  RESULTS
  BP peaked in winter and reached a nadir in summer. After confounder adjustment, systolic BP was 1.0 to 1.7 mm Hg higher January to May, 0.6 mm Hg higher in September and October, and 0.8 mm Hg higher in November and December compared with August. After stratifying by overweight status, BP showed strong seasonal variability among lean women, whereas there were no seasonal trends among overweight women.
  
  
  CONCLUSIONS
  Environmental factors may regulate gestational BP and may be relevant to seasonality of hypertensive disorders of pregnancy.
authors.affiliation: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA. bodnar@edc.pitt.edu
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Bodnar
authors.forename: Ashi
authors.initials: A
authors.lastname: Daftary
authors.forename: Nina
authors.initials: N
authors.lastname: Markovic
authors.forename: Cindy L
authors.initials: CL
authors.lastname: Schatzman
authors.forename: James M
authors.initials: JM
authors.lastname: Roberts
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D015992:Body Mass Index; D003971:Diastole / Q000502:physiology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D011247:Pregnancy / Q000502:physiology*; D012621:Seasons; D013599:Systole / Q000502:physiology