Intrapartum sonography of fetal head in second stage of labor with neuraxial analgesia: a literature review and possible medicolegal aftermath

Intrapartum ultrasound (IU) is a valid support to obstetric management of fetal head progression in the second stage of labor in nulliparous with neuraxial labor analgesia (NLA). Nulliparous with NLA may have a prolonged the second stage of labor. The aim of this literature review was to evaluate the mode of delivery, as well as maternal and fetal morbidities associated with missed progression of fetal head detected with IU in the second stage of labor in nulliparous women with NLA.MATERIALS AND METHODS: The literature review was performed using PubMed, Cochrane, Medline, EMBASE, Scopus, Google Scholar and book chapters searches to identify relevant articles from 2001 to 2019, evaluating the mode of delivery and morbidities of the second stage of labor. Search terms used were “Intrapartum ultrasound”, “dystocia”, “prolonged labor”, “neuraxial analgesia”, “persistent occiput posterior position”, “asynclitism”, “second stage of labor”, “medico-legal aftermath”. Prolonged second stage was defined as three hours and more. Retrospective case series of women with prolonged second stage of labor with NLA were identified. The primary outcome was the incidence of operative vaginal delivery (OVD) and cesarean delivery (CS). RESULTS: The use of NLA may determine a prolonged second stage of labor (PSSL). IU when compared to the traditional vaginal digital examination (VDE) demonstrated the highest degree of diagnostic accuracy. CONCLUSIONS: The use of IU during NLA can aid in the diagnosis of fetal head progression, station or malposition and malrotation, alerts obstetrician on the possibility of dystocic labor, indicating to stop the drug administration in NLA and shift to OVD or CS. Extending the second stage of labor beyond current American College of Obstetricians and Gynecologists (ACOG) recommendations is beneficial. The ISUOG guidelines recommended the clinical application of IU to diagnose the persistent occiput posterior position (POPP) and asynclitism (A) in dystocic labor and produce photographic evidence of the case. Maternal and neonatal complications, medicolegal consequences and litigation can decrease if the IU device is used as good practice.