title: Association of meteorological factors and seasonality with preeclampsia: a 5-year study in northeast of Iran.
abstract: BACKGROUND
  Preeclampsia is one of the common causes of maternal and fetal mortality, and an important problem of pregnancy. This disorder can cause intracranial hemorrhage, intravascular coagulation, pulmonary edema, liver and renal failures and placental abruption.
  
  
  OBJECTIVE
  To evaluate the effects of seasonal and monthly changes of weather, humidity and temperature on the incidence rate of preeclampsia according to the conception and delivery times.
  
  
  METHODS
  Retrospective analysis of hospital records of 20,520 consecutive singleton live birth pregnancies of 20-42 weeks of gestation during 2002-2008 was performed. After including preeclamptic cases, on the basis of American College of obstetricians and gynecologists (ACOG) criteria, gestational age and time of conception was estimated and the mean relative temperature and humidity of each month was derived from monthly climatological data collection of IRAN METEOROLOGICAL ORGANIZATION (IRIMO) between 22 June 2002 and 19 March 2008 (68 months). Statistics of each month's births were registered separately.
  
  
  RESULTS
  Mean maternal age of 262 qualified singleton pregnant women with preeclampsia out of 20,520 deliveries were 26.48 years old and 85.9% of deliveries were done by cesarean section method. Based on time of conception, the highest prevalence was detected in summer, especially in September (11.06875%) and August (10.3053%) and the lowest prevalence was found in winter and early spring, especially in January (5.7552%) and April (5.7252%).
  
  
  CONCLUSIONS
  Seasonal (monthly) variations of the weather (humidity and temperature) have a significant impression on preeclampsia prevalence.
authors.affiliation: Department of Obstetrics and Gynecology and.
authors.forename: Roya
authors.initials: R
authors.lastname: Nasiri
authors.forename: Akram
authors.initials: A
authors.lastname: Ahmadi Shadmehri
authors.forename: Peyman
authors.initials: P
authors.lastname: Khajeh Ghiassi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Sarafraz Yazdi
authors.forename: Morteza
authors.initials: M
authors.lastname: Mazloum Farsi Baf
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007492:Iran / Q000453:epidemiology; D008297:Male; D008685:Meteorological Concepts; D011225:Pre-Eclampsia / Q000453:epidemiology*; D011247:Pregnancy; D015995:Prevalence; D012189:Retrospective Studies; D012621:Seasons; D055815:Young Adult
keywords: Preeclampsia; prevalence; seasonal variations