title: Swimming pool use and birth defect risk.
abstract: OBJECTIVE
  Swimming during pregnancy is recommended. However, the use of swimming pools is also associated with infection by water-borne pathogens and exposure to water disinfection byproducts, which are 2 mechanisms that are suspected to increase risk for birth defects. Thus, we evaluated the relationship between maternal swimming pool use during early pregnancy and risk for select birth defects in offspring.
  
  
  METHODS
  Data were evaluated for nonsyndromic cases with 1 of 16 types of birth defects (n = 191-1829) and controls (n = 6826) from the National Birth Defects Prevention Study delivered during 2000-2006. Logistic regression analyses were conducted separately for each birth defect type. Separate analyses were conducted to assess any pool use (yes vs no) and frequent use (5 or more occasions in 1 month) during the month before pregnancy through the third month of pregnancy.
  
  
  RESULTS
  There was no significant positive association between any or frequent pool use and any of the types of birth defects, even after adjustment for several potential confounders (maternal race/ethnicity, age at delivery, education, body mass index, folic acid use, nulliparity, smoking, annual household income, surveillance center, and season of conception). Frequent pool use was significantly negatively associated with spina bifida (adjusted odds ratio, 0.68; 95% confidence interval, 0.47-0.99). Among offspring of women 20 years old or older, pool use was associated with gastroschisis (adjusted odds ratio, 1.3; 95% confidence interval, 1.0-1.8), although not significantly so.
  
  
  CONCLUSIONS
  We observed little evidence suggesting teratogenic effects of swimming pool use. Because swimming is a common and suggested form of exercise during pregnancy, these results are reassuring.
authors.affiliation: Division of Epidemiology, Human Genetics, and Environmental Sciences, Human Genetics Center, University of Texas School of Public Health, Houston, TX, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Agopian
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Lupo
authors.forename: Mark A
authors.initials: MA
authors.lastname: Canfield
authors.forename: Laura E
authors.initials: LE
authors.lastname: Mitchell
mesh_terms: D000328:Adult; D000013:Congenital Abnormalities / Q000209:etiology*; D005260:Female; D020139:Gastroschisis / Q000209:etiology; D006801:Humans; D016015:Logistic Models; D011247:Pregnancy; D012306:Risk; D016135:Spinal Dysraphism / Q000209:etiology; D013551:Swimming Pools
keywords: Texas; birth defects; gastroschisis; pregnancy; swimming pool