title: Pubic arch angle in prolonged second stage of labor: clinical significance.
abstract: OBJECTIVE
  To evaluate the clinical significance of the pubic arch angle (PAA) measured by transperineal ultrasound during prolonged second stage of labor.
  
  
  METHODS
  We evaluated prospectively 62 women ≥ 37 weeks of gestation with failure to progress in the second stage of labor. Transperineal ultrasound (transverse plane) was used to measure the pubic arch angle. Correlations with fetomaternal characteristics, mode of delivery and perinatal outcome were evaluated.
  
  
  RESULTS
  The mean PAA was 101.1° (± 13.1°; range, 80°-135°). We found a negative correlation with maternal age. Patients with an occipitotransverse fetal position had a significantly smaller angle compared with those with occipitoanterior positions (94.3° ± 5.5° vs. 103.2° ± 14.8°, P < 0.05), as did those with operative deliveries compared with those with spontaneous vaginal delivery (97.1° ± 11.5° vs. 110.1° ± 14.0°, P < 0.05). The prediction of operative delivery in prolonged second stage of labor by receiver-operating characteristics curve using PAA alone yielded an area under the curve of 0.75. The predicted probability for operative delivery increased as PAA decreased, with an odds ratio of 0.933 for each decrease in angle of 1°.
  
  
  CONCLUSIONS
  Our study suggests a correlation between the PAA and mode of delivery in prolonged second stage of labor. This may be used as an adjunctive parameter when considering delivery mode.
authors.affiliation: Chaim Sheba Medical Center, Department of Obstetrics and Gynecology, Ramat Gan, Israel, affiliated with the Sackler School of Medicine, Tel-Aviv University, Tel Aviv, Israel. yinon-si@inter.net.il
authors.forename: Y
authors.initials: Y
authors.lastname: Gilboa
authors.forename: Z
authors.initials: Z
authors.lastname: Kivilevitch
authors.forename: M
authors.initials: M
authors.lastname: Spira
authors.forename: A
authors.initials: A
authors.lastname: Kedem
authors.forename: E
authors.initials: E
authors.lastname: Katorza
authors.forename: O
authors.initials: O
authors.lastname: Moran
authors.forename: R
authors.initials: R
authors.lastname: Achiron
mesh_terms: D000328:Adult; D036861:Delivery, Obstetric / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007748:Labor Stage, Second / Q000502:physiology*; D010502:Perineum / Q000000981:diagnostic imaging; D011247:Pregnancy; D011446:Prospective Studies; D011630:Pubic Bone / Q000033:anatomy & histology*; D011631:Pubic Symphysis / Q000033:anatomy & histology*; D013997:Time Factors; D016216:Ultrasonography, Prenatal / Q000379:methods*; D055815:Young Adult