title: Effect of maternal height and weight on risk of preterm birth in singleton and twin births resulting from in vitro fertilization: a retrospective cohort study using the Society for Assisted Reproductive Technology Clinic Outcome Reporting System.
abstract: OBJECTIVE
  To examine the effect of height, weight, and body mass index (BMI) on the risk of preterm birth of singleton and twin pregnancies conceived by vitro fertilization (IVF).
  
  
  METHODS
  Retrospective cohort study using 2006-2008 data from the Society for Reproductive Technology Clinic Outcome Reporting System (SART CORS).
  
  
  METHODS
  SART-associated assisted reproductive technology programs.
  
  
  METHODS
  56,556 singleton and 23,804 twin live births resulting from fresh nondonor IVF cycles.
  
  
  METHODS
  None.
  
  
  METHODS
  Rates of very early preterm (VEPTB; <28 weeks), very preterm (VPTB; <32 weeks), and preterm birth (<37 weeks) births.
  
  
  RESULTS
  In both singleton and twin births, increased maternal height was associated with a decreased risk of preterm birth. Maternal overweight and obesity were associated with significantly increased risk of VEPTB and VPTB in twin pregnancies. For very obese women (BMI > 35 kg/m(2)) twins were associated with a threefold increased risk of VEPTB (6.1% vs. 2.0%) and a twofold increased risk of VPTB (11.5% vs. 5.9%) compared with women of normal weight (BMI 18.4-24.9 kg/m(2)).
  
  
  CONCLUSIONS
  Obesity and short stature significantly increase the risk of VEPTB and VPTB in twins conceived by IVF.
authors.affiliation: Section of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Louisiana State University School of Medicine, New Orleans, and Fertility Institute of New Orleans, Mandeville, Louisiana, USA. renee@fertilityinstitute.com
authors.forename: Richard P
authors.initials: RP
authors.lastname: Dickey
authors.forename: Xu
authors.initials: X
authors.lastname: Xiong
authors.forename: Rebekah E
authors.initials: RE
authors.lastname: Gee
authors.forename: Gabriella
authors.initials: G
authors.lastname: Pridjian
mesh_terms: D001827:Body Height; D015992:Body Mass Index; D001835:Body Weight; D016009:Chi-Square Distribution; D015331:Cohort Studies; D005260:Female; D005307:Fertilization in Vitro / Q000009:adverse effects*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D016015:Logistic Models; D009765:Obesity / Q000150:complications* / Q000503:physiopathology; D016017:Odds Ratio; D050177:Overweight / Q000150:complications* / Q000503:physiopathology; D011247:Pregnancy; D059285:Pregnancy, Twin; D047928:Premature Birth / Q000209:etiology*; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014481:United States