Dynamic ultrasound control in the second stage of labor

Objective. To establish ultrasound characteristics of the dynamics of the fetal head descent along the birth canal during the uncomplicated second stage of labor in the occiput anterior and posterior positions. Materials and methods. The prospective study included 198 women in labor. Spontaneous birth occurred in 180 of them, without the use of augmentation of labor or operative delivery. The remaining 18 women were excluded from the final analysis due to the use of augmentation of labor or operative delivery. The average gestational age was 39 3/7 weeks. The average weight of newborns was 3394 grams; all children were born with an Apgar score of 8 points or more at 5 minutes. All patients in the second stage of labor underwent hourly transperineal ultrasound to assess the angle of progression (AoP) and the delta angle of progression (ΔAoP). According to the AoP values, the following groups were formed: Group 1 - AoP less than 120°, which corresponds to the fetal head station on the parallel plane -1 to -2 cm; Group 2 – AoP 120-144 °, parallel plane 0 to +2; Group 3 – 145–170°, parallel plane from +2 to +5 cm, Group 4 – AoP more than 170°, parallel plane > +5 cm. Statistical analyses were carried out with the use of IBM SPSS Statistics 27 software; the significance of differences between the groups was confirmed by the Long Rank test (p < 0.001) and the Kruskal–Wallis criterion (p < 0.005). Results. In cases of delivery with occiput anterior position, the time to birth was 177 (177–250) min in group 1, 100 (35–240) min in group 2, 75 (30–170) min in group 3, and 35 (15–75) min in group 4. There was no significant difference in ΔAoP between the groups — 16.6 ± 8.5 (10.1–27.1°). In the cases of delivery with posterior occipital position, no patient in group 1 had spontaneous labor with AoP <120°, while the time to birth was 110 (45–240) min in group 2, 75 (110–170) min in group 3, and 65 (18–110) min in group 4. ΔAoP was 12.5 ± 8.5 (11–15.6°). Conclusion. The management of labor with dynamic ultrasound control provides the possibility to obtain objective criteria for the normal course of the second stage of labor, to improve the quality and reliability of the information received, to eliminate unnecessary interventions, and to reduce the number of vaginal digital examinations during childbirth, which has a positive effect on perinatal outcomes, reduces the risk of purulent-septic complications in the mothers, and increases the patients comfort during childbirth.