title: Prediction of intrapartum Cesarean delivery for non-reassuring fetal status after a successful external cephalic version by a low pre-version pulsatility index of the fetal middle cerebral artery.
abstract: OBJECTIVE
  To determine whether a pre-version Doppler assessment of fetal cerebral and umbilical blood flow can predict the ultimate need for intrapartum Cesarean delivery after a successful external cephalic version (ECV).
  
  
  METHODS
  A prospective observational study on women undergoing ECV between 36 and 38 gestational weeks was performed over a 5-year period. The pulsatility index (PI) of the fetal middle cerebral artery (MCA) and umbilical artery, heart rate and amniotic fluid index were measured before ECV. Women who had successful ECV were then divided into three groups according to the mode of delivery: (1) vaginal delivery, (2) intrapartum Cesarean delivery for poor progress and (3) intrapartum Cesarean delivery for non-reassuring fetal status. The fetal blood flow parameters were compared between the groups. Potential predictors were further analyzed using receiver-operating characteristics curves.
  
  
  RESULTS
  Of 174 women with successful ECV, 140 (80.5%) had vaginal delivery, 19 (10.9%) required emergency intrapartum Cesarean delivery for non-reassuring fetal status and 15 (8.6%) for poor progress. MCA-PI was significantly lower in the group with non-reassuring fetal status. MCA-PI is predictive of intrapartum Cesarean delivery (area under the curve = 0.68, P = 0.021). The sensitivity and specificity at a cut-off level of 1.4 were 62.5% and 76%, respectively, while at a cut-off level of 1.5 they were 68.8% and 63.5%, respectively.
  
  
  CONCLUSIONS
  Intrapartum Cesarean delivery for non-reassuring fetal status after successful ECV is associated with a lower pre-version fetal MCA-PI.
authors.affiliation: Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong, China SAR. tyleung@cuhk.edu.hk
authors.forename: T Y
authors.initials: TY
authors.lastname: Leung
authors.forename: W Y
authors.initials: WY
authors.lastname: Fok
authors.forename: L W
authors.initials: LW
authors.lastname: Chan
authors.forename: L W
authors.initials: LW
authors.lastname: Law
authors.forename: T K
authors.initials: TK
authors.lastname: Lau
mesh_terms: D001946:Breech Presentation; D002585:Cesarean Section; D005260:Female; D006340:Heart Rate, Fetal; D006801:Humans; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011256:Pregnancy Outcome; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D011673:Pulsatile Flow; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014219:Trial of Labor; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal; D014469:Umbilical Arteries / Q000000981:diagnostic imaging; D014710:Version, Fetal