title: Explaining the association of maternal age with Cesarean delivery for nulliparous and parous women.
abstract: METHODS
  We used data on 6,805 live births from the National Maternal and Infant Health Survey to examine the positive association between maternal age and Cesarean delivery.
  
  
  RESULTS
  For parous women, the unadjusted risk ratio [RR] for Cesarean, comparing 35 year olds with 20 year olds, was estimated to be 1.40 [95% confidence limits (CL)=1.18, 1.65]; this association disappeared upon adjustment for obstetrical predictors and other factors (adjusted RR=1.04; 95% CL=0.80, 1.35). In contrast, for nulliparous women, the unadjusted risk ratio was 2.16 (95% CL=1.78, 2.63) and remained substantial upon adjustment (RR=1.74; 95% CL=1.25, 2.43).
  
  
  CONCLUSIONS
  These results, along with baseline risk information, suggest that older nulliparous women and their obstetricians should be the target of future efforts to control Cesarean rates.
authors: Center for Statistical Sciences and the Department of Community Health, Brown University School of Medicine, Box G-H, Providence, RI 02912, USA. igareen@stat.brown.edu
authors: Ilana F
authors: IF
authors: Gareen
authors: Hal
authors: H
authors: Morgenstern
authors: Sander
authors: S
authors: Greenland
authors: Deidre Spelliscy
authors: DS
authors: Gifford
mesh_terms: D000328:Adult; D002585:Cesarean Section; D003627:Data Interpretation, Statistical; D005260:Female; D006306:Health Surveys; D006801:Humans; D008423:Maternal Age; D007744:Obstetric Labor Complications / Q000601:surgery; D010298:Parity; D011247:Pregnancy; D018566:Pregnancy, High-Risk; D011295:Prenatal Care; D012306:Risk