302: Shoulder dystocia maneuvers and neonatal outcomes

301 A new standard for fetal descent in labor Anna Graseck, Kimberly Roehl, Anthony Odibo, eorge Macones, Alison Cahill Washington University in St. Louis, Obstetrics and Gynecology, t. Louis, MO OBJECTIVE: Recent work using a contemporary population and modrn statistical methods has redefined the rate of cervical dilation in ormal labor. However, modern norms for changes in station in labor ave not been developed. We developed new norms for fetal descent n labor, and compared the rate of fetal descent among women by arity, and among those in spontaneous and induced labor. STUDY DESIGN: A retrospective cohort study was conducted of consective term, vertex singletons from 2004-2008 who delivered vaginally. xtensive data were collected from the medical records, including ervical exams (allowing complete reconstruction of the labor curves) nd obstetric and neonatal outcomes. Station was measured on a 3 o 3 scale. A repeated-measures analysis was used to construct avrage descent curves, stratified by parity and labor type. Interval-cenored regression was used to estimate duration of labor, from each evel of station to the next, stratified by parity and labor type, and djusted for race and fetal macrosomia. RESULTS: Of 5,388 consecutive term births, 1,992 (37%) were nulliprous. Sixty-two percent (n 3,373) were augmented or induced. ultiparous women had faster fetal descent at all stations except from 2 to 3 station, in both unadjusted and adjusted analyses. Median escent from one station point to another ranged from 0.1 1.6 hours, ut the 95th percentiles encompassed over 12 hours at the same staion in women who eventually achieved vaginal delivery. In stratified nalysis of spontaneous and non-spontaneous labor, spontaneous laorers had faster descent. CONCLUSION: Multiparas have faster fetal descent than nulliparas. Women in spontaneous labor also have faster fetal descent compared to those being induced or augmented.