title: Vasoactive exposures during pregnancy and risk of microtia.
abstract: BACKGROUND
  Little is known about the etiology of nonsyndromic microtia. This study investigated the hypothesis that microtia is caused by vascular disruption.
  
  
  METHODS
  The study analyzed data from the population-based National Birth Defects Prevention Study (NBDPS) for deliveries between 1997 and 2005. Four hundred eleven nonsyndromic cases of microtia, with or without additional defects, were compared to 6560 nonmalformed infants with respect to maternal exposures to vasoactive medications and smoking during the periconceptional period and conditions that have previously been associated with vascular events (multiple gestation, maternal history of type 1, type 2, or gestational diabetes, and hypertension). Odds ratios (ORs) were estimated with multivariable models, controlling for the effects of race/ethnicity, education, periconceptional folic acid use, and study center.
  
  
  RESULTS
  Risk estimates for vasoactive medications and smoking were not meaningfully increased. Maternal type 1/2 diabetes was diagnosed before or during the index pregnancy in 4% and 1% of cases, respectively, compared to 1% and 0.05% of controls; the adjusted OR for these two groups combined was 7.2 (95% confidence interval [CI], 3.9-13.1). Gestational diabetes was observed for 9% of cases and 6% of controls; the OR was moderately elevated (OR, 1.4; 95% CI, 0.9-2.0). ORs were also increased for multiple gestations (OR, 2.5; 95% CI, 1.5-4.2) and pre-existing hypertension (OR, 1.6; 95% CI, 1.0-2.5).
  
  
  CONCLUSIONS
  Because ORs were only elevated for diabetes and not for vasoactive exposures or other potential vascular events, findings suggest that some microtia occurrences may be part of the diabetic embryopathy rather than manifestations of vascular disruption. Birth Defects Research (Part A), 2013. © 2012 Wiley Periodicals, Inc.
authors.affiliation: Slone Epidemiology Center at Boston University, Boston, MA 02215, USA. cvanben@bu.edu
authors.forename: Carla M
authors.initials: CM
authors.lastname: Van Bennekom
authors.forename: Allen A
authors.initials: AA
authors.lastname: Mitchell
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Moore
authors.forename: Martha M
authors.initials: MM
authors.lastname: Werler
mesh_terms: D002317:Cardiovascular Agents / Q000009:adverse effects*; D000013:Congenital Abnormalities / Q000453:epidemiology / Q000209:etiology*; D065817:Congenital Microtia; D048909:Diabetes Complications / Q000188:drug therapy* / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000453:epidemiology; D016640:Diabetes, Gestational / Q000453:epidemiology; D004423:Ear / Q000002:abnormalities; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D018811:Maternal Exposure / Q000009:adverse effects*; D016017:Odds Ratio; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000453:epidemiology*; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D014481:United States / Q000453:epidemiology
chemical_list: D002317:Cardiovascular Agents