title: Association of Recorded Estimated Fetal Weight and Cesarean Delivery in Attempted Vaginal Delivery at Term.
abstract: OBJECTIVE
  To evaluate the association between documentation of estimated fetal weight, and its value, with cesarean delivery.
  
  
  METHODS
  This was a secondary analysis of a multicenter observational cohort of 115,502 deliveries from 2008 to 2011. Data were abstracted by trained and certified study personnel. We included women at 37 weeks of gestation or greater attempting vaginal delivery with live, nonanomalous, singleton, vertex fetuses and no history of cesarean delivery. Rates and odds ratios (ORs) were calculated for women with ultrasonography or clinical estimated fetal weight compared with women without documentation of estimated fetal weight. Further subgroup analyses were performed for estimated fetal weight categories (less than 3,500, 3,500-3,999, and 4,000 g or greater) stratified by diabetic status. Multivariable analyses were performed to adjust for important potential confounding variables.
  
  
  RESULTS
  We included 64,030 women. Cesarean delivery rates were 18.5% in the ultrasound estimated fetal weight group, 13.4% in the clinical estimated fetal weight group, and 11.7% in the no documented estimated fetal weight group (P<.001). After adjustment (including for birth weight), the adjusted OR of cesarean delivery was 1.44 (95% confidence interval [CI] 1.31-1.58, P<.001) for women with ultrasound estimated fetal weight and 1.08 for clinical estimated fetal weight (95% CI 1.01-1.15, P=.017) compared with women with no documented estimated fetal weight (referent). The highest estimates of fetal weight conveyed the greatest odds of cesarean delivery. When ultrasound estimated fetal weight was 4,000 g or greater, the adjusted OR was 2.15 (95% CI 1.55-2.98, P<.001) in women without diabetes and 9.00 (95% CI 3.65-22.17, P<.001) in women with diabetes compared to those with estimated fetal weight less than 3,500 g.
  
  
  CONCLUSIONS
  In this contemporary cohort of women attempting vaginal delivery at term, documentation of estimated fetal weight (obtained clinically or, particularly, by ultrasonography) was associated with increased odds of cesarean delivery. This relationship was strongest at higher fetal weight estimates, even after controlling for the effects of birth weight and other factors associated with increased cesarean delivery risk.
authors: Departments of Obstetrics and Gynecology, Women & Infants Hospital, Brown University, Providence, Rhode Island, MetroHealth Medical Center-Case Western Reserve University, Cleveland, Ohio, Columbia University, New York, New York, the University of Utah Health Sciences Center, Salt Lake City, Utah, the University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, The Ohio State University, Columbus, Ohio, the University of Alabama at Birmingham, Birmingham, Alabama, Wayne State University, Detroit, Michigan, Brown University, Providence, Rhode Island, the University of Texas Health Science Center at Houston-Children's Memorial Hermann Hospital, Houston, Texas, the Oregon Health & Science University, Portland, Oregon; and the George Washington University Biostatistics Center, Washington, DC; and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland.
authors: Rosemary J
authors: RJ
authors: Froehlich
authors: Grecio
authors: G
authors: Sandoval
authors: Jennifer L
authors: JL
authors: Bailit
authors: William A
authors: WA
authors: Grobman
authors: Uma M
authors: UM
authors: Reddy
authors: Ronald J
authors: RJ
authors: Wapner
authors: Michael W
authors: MW
authors: Varner
authors: John M
authors: JM
authors: Thorp
authors: Mona
authors: M
authors: Prasad
authors: Alan T N
authors: ATN
authors: Tita
authors: George
authors: G
authors: Saade
authors: Yoram
authors: Y
authors: Sorokin
authors: Sean C
authors: SC
authors: Blackwell
authors: Jorge E
authors: JE
authors: Tolosa
mesh_terms: D000328:Adult; D001724:Birth Weight; D002585:Cesarean Section / Q000379:methods / Q000706:statistics & numerical data; D015331:Cohort Studies; D005260:Female; D020567:Fetal Weight; D005865:Gestational Age; D006801:Humans; D049451:Nomograms; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D013223:Statistics as Topic; D047929:Term Birth; D016216:Ultrasonography, Prenatal / Q000379:methods / Q000706:statistics & numerical data; D014481:United States / Q000453:epidemiology