Intrapartum ultrasound

The use of intrapartum ultrasound has increased extensively over the last two decades. This increase is mostly driven by its higher accuracy, reliability and intra- and interobserver agreement compared to the traditionally-used vaginal examination for the assessment of several labor parameters. Moreover, it is less invasive, better tolerated by women and has a lower risk of pregnancy-related infections. The most important parameters that can be assessed by intrapartum ultrasound include the fetal head position, station and attitude. In the first section of this review, we explain how to use intrapartum ultrasound to assess these parameters, providing a broad overview of the different available techniques. The second section describes the indications of intrapartum ultrasound and provides some insight on how intrapartum ultrasound may help to improve management of abnormal labor. In the last section, we discuss the future perspectives of intrapartum ultrasound. This includes topics such as the incorporation of new labor parameters, such as maternal pelvimetry, molding and caput succedaneum; the development of "sonopartograms", and the use of artificial intelligence. This review is intended for obstetricians and midwives involved in daily practice in the labor ward.