Process of fetal head descent as recorded by ultrasonography: How does this compare with the conventional first stage of labor?

Objective To construct an ultrasound partogram using serial transperineal sonographic measurements of the angle of fetal head progression during the first stage of labor, and to compare it with a conventional partogram based on digital vaginal examinations. Methods Between 2017 and 2018, a prospective cohort study at Drum Tower Hospital, Nanjing, China, recruited 375 nulliparous women with singleton pregnancy and spontaneous onset of labor at 37 or more gestational weeks. Transperineal ultrasound scans were performed to measure the angle of progression (AoP) every 0.5-1 h until the second stage. Vaginal examinations were also used to measure cervical dilatation. Repeated-measures analysis was used to generate labor curves. Results The labor curve generated by AoP had a pattern similar to that based on cervical dilatation. There was an initial slow period lasting approximately 5.5 h until the cervical dilatation or AoP reached the inflection point (4 cm and 119 degrees, respectively), followed by a second, more rapid period, lasting approximately 2.5 h. Conclusion Based on ultrasound data, it was feasible to construct an angle of progression partogram of the first stage of labor, which was similar in pattern to the partogram based on cervical dilatation measured in the same cohort.

Automated summary

This study demonstrated the feasibility of constructing an angle of progression partogram of the first stage of labor based on ultrasound measurements, which showed a pattern similar to the conventional partogram based on cervical dilatation in the same cohort.