Intrapartum Sonography for Difficult Labor

Area of Science:

• Obstetrics and Gynecology
• Medical Imaging
• Fetal Monitoring

Background:

• Difficult labor, including protracted dilatation and arrested descent, contributes significantly to cesarean deliveries and instrumental birth-related morbidities.
• Clinical decisions during labor are primarily based on digital vaginal examination, which is uncomfortable, requires repetition, and is least reliable during critical moments.
• Limitations of digital examination include inaccuracies in assessing fetal head position, attitude, and station, particularly when obscured by caput succedaneum or molding.

Purpose of the Study:

• To evaluate the utility of intrapartum sonography as an adjunct to digital vaginal examination in managing labor.
• To address specific clinical questions regarding fetal head position, rotation likelihood, flexion, engagement, and descent using sonography.
• To provide guidance for obstetricians and residents on integrating sonography into labor management.

Main Methods:

• Sonography performed with a standard curvilinear transducer on labor wards.
• Assessment of fetal head position using midline cerebral echo, orbits, cerebellum, and cervical spine.
• Quantification of fetal head flexion, asynclitism, station, and progression using specific sonographic measurements (e.g., occiput-spine angle, angle of progression).

Main Results:

• Sonographic determination of occiput position is more accurate than digital examination.
• Adding sonography improves the accuracy of knowing fetal head position.
• Measurements of station and attitude are reproducible and associated with delivery mode, though thresholds require further validation.

Conclusions:

• Intrapartum sonography offers a more accurate and better-tolerated alternative to repeated digital examinations for assessing fetal head parameters.
• Sonography can aid in clinical decision-making for uncertain fetal head positions, slow labor, and before assisted vaginal birth.
• Sonography should be used as an adjunct to clinical examination when uncertainty exists or when more accurate assessment could alter management.