title: Are Meteorological Conditions within the First Trimester of Pregnancy Associated with the Risk of Severe Pre-Eclampsia?
abstract: BACKGROUND
  Severe pre-eclampsia (SPE) is the second cause of maternal death in developed countries. The literature suggests different risk factors for early- and late-onset pre-eclampsia. SPE is usually related to the early-onset type. Pre-eclampsia rate exhibits seasonal variation. However, the weather-SPE association is still unknown. We examined the associations between maternal exposure to meteorological parameters after conception and SPE.
  
  
  METHODS
  From 2008 to 2011, all deliveries of women living in the Yvelines area, France, have been prospectively registered. Meteorological measurements from weather stations scattered inside Yvelines were averaged on two exposure windows: early-pregnancy (30 days after conception) and first-trimester (90 days after conception). The relationship between SPE and season of conception was also examined. Hierarchical complementary log-log regression models were used to estimate the weather-SPE association.
  
  
  RESULTS
  SPE was diagnosed in 526 (0.8%) out of 63,633 singleton pregnancies. Increasing temperature or sunshine across both windows was associated with increased SPE risk. Early-pregnancy minimum temperature showed the strongest effect with adjusted odds ratio (OR) per 1 degree Celsius: 1.03 [95% confidence interval (CI) 1.01, 1.04]. The risk of SPE was higher when conception was in summer as compared to winter (OR 1.53, 95% CI 1.27, 1.85). Effect estimates showed only small variations in sensitivity analyses.
  
  
  CONCLUSIONS
  Our findings of a weather impact during early pregnancy on SPE may provide a new clue for understanding the causes of pre-eclampsia. Further investigation into the biologic mechanisms for this finding is required.
authors.affiliation: UPRES EA 2506 (Santé-Environnement Vieillissement), UFR Sciences de la Santé Paris Île-de-France Ouest, Université Versailles St-Quentin-en-Yvelines, Boulogne-Billancourt, France.
authors.forename: Thi-Chien
authors.initials: TC
authors.lastname: Tran
authors.affiliation: UPRES EA 2506 (Santé-Environnement Vieillissement), UFR Sciences de la Santé Paris Île-de-France Ouest, Université Versailles St-Quentin-en-Yvelines, Boulogne-Billancourt, France.
authors.forename: Ariane
authors.initials: A
authors.lastname: Boumendil
authors.affiliation: Département Gynécologie-Obstétrique, Hôpital Poissy-Saint-Germain, Poissy, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Bussieres
authors.affiliation: Réseau Périnatal de l'Agence Régionale de Santé Île-de-France (Périnat-ARS-IDF), Paris, France.
authors.forename: Elodie
authors.initials: E
authors.lastname: Lebreton
authors.affiliation: Unité de Recherche Clinique Hôpital Universitaire Paris Île-de-France Ouest, Boulogne-Billancourt, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Ropers
authors.affiliation: Département Gynécologie-Obstétrique, Hôpital Poissy-Saint-Germain, Poissy, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Rozenberg
authors.affiliation: UPRES EA 2506 (Santé-Environnement Vieillissement), UFR Sciences de la Santé Paris Île-de-France Ouest, Université Versailles St-Quentin-en-Yvelines, Boulogne-Billancourt, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Aegerter
mesh_terms: D000328:Adult; D005260:Female; D005306:Fertilization / Q000502:physiology*; D005602:France / Q000453:epidemiology; D006801:Humans; D011225:Pre-Eclampsia / Q000453:epidemiology / Q000209:etiology*; D011247:Pregnancy; D011261:Pregnancy Trimester, First / Q000502:physiology*; D012307:Risk Factors; D012621:Seasons; D013696:Temperature; D013997:Time Factors
keywords: environment; meteorological; pre-eclampsia; pregnancy; weather