Objective: Our purpose was to determine the rate of associated risk factors for shoulder dystocia from a large cohort of patients delivered within our Southern California perinatal program. Study design: A retrospecti...Objective: Our purpose was to determine the rate of associated risk factors for shoulder dystocia from a large cohort of patients delivered within our Southern California perinatal program. Study design: A retrospective analysis was performed of patients delivered from January 1991 to June 2001. Patients with and without shoulder dystocia were identified from our computer- stored perinatal database and compared. Statistical methods used included: χ 2 test, t test, calculation of odds ratios, and Fisher exact test, as indicated. Results: Among the 267,228 vaginal births during the study period, there were 1,686 cases of shoulder dystocia (rate 0.6% ). Rates for operative vaginal delivery, diabetes, epidural use, multiparity, and postdatism were similar among cases with and without shoulder dystocia. The clinical triad of oxytocin use, labor induction, and birth weight greater than 4,500 g yielded a cumulative odds ratio of 23.2 (95% CI 17.3- 31.0) for shoulder dystocia, but its sensitivity and positive predictive value were only 12.4% and 3.4% , respectively. Conclusion: Historic obstetric risk factors for shoulder dystocia are not useful predictors for the event. Furthermore, although shoulder dystocia was observed more frequently with increasing birth weight, current limitations in estimating birth weight antenatally with accuracy preclude its practical use as a reliable predictor.展开更多
Objective: The purpose of this study was to characterize placental expression of the prostaglandin synthase enzymes cyclooxygenase (COX) - 1 and - 2 and prostaglandin dehydrogenase (PGDH, a degrading enzyme). Study de...Objective: The purpose of this study was to characterize placental expression of the prostaglandin synthase enzymes cyclooxygenase (COX) - 1 and - 2 and prostaglandin dehydrogenase (PGDH, a degrading enzyme). Study design: Forty- one women between 20 and 37 weeks’ gestation and 39 matched term controls with either spontaneous labor or premature rupture of membranes were enrolled in a prospective case- control study. The relative amounts of placental RNAs at delivery were determined using real- time polymerase chain reaction (PCR). Results: Placental COX- 1 RNA decreased with advancing gestational age at delivery (R2 = 0.13, P = .001), and increased by 43% when chorioamnionitis was present (P = .006). Among patients presenting at term, oxytocin use was associated with 30% lower expression of COX- 1 (P = .01). COX- 2 and PGDH were not associated with these variables. Conclusion: Placental COX- 1 RNA at delivery decreases with advancing gestational age and with oxytocin use at term. Thus, expression of placental COX- 1 is not constitutive. Placental expression of COX- 2 and PGDH do not correlate with gestational age, chorioamnionitis, or oxytocin use.展开更多
文摘Objective: Our purpose was to determine the rate of associated risk factors for shoulder dystocia from a large cohort of patients delivered within our Southern California perinatal program. Study design: A retrospective analysis was performed of patients delivered from January 1991 to June 2001. Patients with and without shoulder dystocia were identified from our computer- stored perinatal database and compared. Statistical methods used included: χ 2 test, t test, calculation of odds ratios, and Fisher exact test, as indicated. Results: Among the 267,228 vaginal births during the study period, there were 1,686 cases of shoulder dystocia (rate 0.6% ). Rates for operative vaginal delivery, diabetes, epidural use, multiparity, and postdatism were similar among cases with and without shoulder dystocia. The clinical triad of oxytocin use, labor induction, and birth weight greater than 4,500 g yielded a cumulative odds ratio of 23.2 (95% CI 17.3- 31.0) for shoulder dystocia, but its sensitivity and positive predictive value were only 12.4% and 3.4% , respectively. Conclusion: Historic obstetric risk factors for shoulder dystocia are not useful predictors for the event. Furthermore, although shoulder dystocia was observed more frequently with increasing birth weight, current limitations in estimating birth weight antenatally with accuracy preclude its practical use as a reliable predictor.
文摘Objective: The purpose of this study was to characterize placental expression of the prostaglandin synthase enzymes cyclooxygenase (COX) - 1 and - 2 and prostaglandin dehydrogenase (PGDH, a degrading enzyme). Study design: Forty- one women between 20 and 37 weeks’ gestation and 39 matched term controls with either spontaneous labor or premature rupture of membranes were enrolled in a prospective case- control study. The relative amounts of placental RNAs at delivery were determined using real- time polymerase chain reaction (PCR). Results: Placental COX- 1 RNA decreased with advancing gestational age at delivery (R2 = 0.13, P = .001), and increased by 43% when chorioamnionitis was present (P = .006). Among patients presenting at term, oxytocin use was associated with 30% lower expression of COX- 1 (P = .01). COX- 2 and PGDH were not associated with these variables. Conclusion: Placental COX- 1 RNA at delivery decreases with advancing gestational age and with oxytocin use at term. Thus, expression of placental COX- 1 is not constitutive. Placental expression of COX- 2 and PGDH do not correlate with gestational age, chorioamnionitis, or oxytocin use.
