title: Maternal obesity and risk of Down syndrome in the offspring.
abstract: OBJECTIVE
  The objective of this article is to determine if maternal obesity is associated with an increased risk of Down syndrome in the offspring and whether the risk estimates for trisomy 21 based on combined screening is affected by maternal body mass index (BMI).
  
  
  METHODS
  Study group I consisted of a nationwide cohort of 1 568 604 women giving birth; outcome was infants born with Down syndrome [Correction made here after initial online publication.]. Adjustment was made for maternal age. Study group II consisted of 10 224 women undergoing 1st trimester combined screening. Outcome was risk assessment for Down syndrome. All women were divided into six BMI groups, and outcomes were evaluated over the BMI strata with BMI 18.5 to 24.9 as reference and correcting for maternal age.
  
  
  RESULTS
  Obese women had an increased risk for giving birth to an infant with Down syndrome compared with normal-weight women, BMI 30 to 34.9 odds ratio (OR) 1.31 [95% confidence interval (CI) 1.10-1.55], BMI 35 to 39.9 OR 1.12 (95% CI 0.82-1.53), BMI ≥ 40 OR 1.56 (95% CI 1.00-2.43). The observed and the expected numbers of women with a risk of Down syndrome >1/300 based on 1st trimester combined screen and maternal age were similar in each BMI group.
  
  
  CONCLUSIONS
  Maternal obesity seems to increase the risk for Down syndrome births. The risk estimate for Down syndrome with 1st trimester combined screening is unaffected by BMI.
authors: Department of Clinical and Experimental Medicine, Linköping University, Department of Obstetrics and Gynecology, County Council of Östergötland, Linköping, Sweden.
authors: Eric
authors: E
authors: Hildebrand
authors: Bengt
authors: B
authors: Källén
authors: Ann
authors: A
authors: Josefsson
authors: Tomas
authors: T
authors: Gottvall
authors: Marie
authors: M
authors: Blomberg
mesh_terms: D000328:Adult; D015992:Body Mass Index; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood; D015331:Cohort Studies; D004314:Down Syndrome / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008423:Maternal Age; D048208:Nuchal Translucency Measurement; D009765:Obesity / Q000453:epidemiology*; D016017:Odds Ratio; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology*; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism; D011296:Prenatal Diagnosis; D012306:Risk; D018570:Risk Assessment
chemical_list: D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A; C579283:PAPPA protein, human