Long-term trends in the incidence and management of shoulder dystocia in a tertiary obstetric unit in Hong Kong

Introduction: Because there have been changes in the management of macrosomic pregnancies and shoulder dystocia in the past decade, this study was conducted to compare the incidences of shoulder dystocia and perinatal outcomes between the periods of 2000-2009 and 2010-2019.Methods: This retrospective study was conducted in a tertiary obstetric unit. All cases of shoulder dystocia were identified using the hospital's electronic database. The incidences, maternal and fetal characteristics, obstetric management methods, and perinatal outcomes were compared between the two study periods.Results: The overall incidence of shoulder dystocia decreased from 0.23% (134/58 326) in 2000-2009 to 0.16% (108/65 683) in 2010-2019 (P=0.009), mainly because of the overall decline in the proportion of babies with macrosomia (from 3.3% to 2.3%; P<0.001). The improved success rates of the McRoberts' manoeuvre (from 31.3% to 47.2%; P=0.012) and posterior arm extraction (from 52.9% to 92.3%; P=0.042) allowed a greater proportion of affected babies to be delivered within 2 minutes (from 59.0% to 79.6%; P=0.003). These changes led to a significant reduction in the proportion of fetuses with low Apgar scores: <5 at 1 minute of life (from 13.4% to 5.6%; P=0.042) and <7 at 5 minutes of life (from 11.9% to 4.6%; P=0.045). Conclusion: More proactive management of macrosomic pregnancies and enhanced training in the acute management of shoulder dystocia led to significant improvements in shoulder dystocia incidence and perinatal outcomes from 2000-2009 to 2010-2019.