Fetal head progression and regression on maternal pushing at term and labor outcome

Abstract

Objectives The aim of our study was two‐fold. First, to evaluate the association between the change in the angle of progression (AoP) on maternal pushing and labor outcome. Second, to assess the incidence and clinical significance of the reduction of AoP on maternal pushing. Methods This was a prospective cohort study of nulliparous women with singleton pregnancy at term. AoP was measured at rest and on maximum Valsalva maneuver before the onset of labor, and the difference between AoP on maximum Valsalva and that at rest (ΔAoP) was calculated for each woman. Following delivery and data collection, we assessed the association between ΔAoP and various labor outcomes, including Cesarean section (CS), duration of the first, second and active second stages of labor, Apgar score and admission to the neonatal intensive care unit (NICU). The prevalence of women with reduction of AoP on maximum Valsalva maneuver (AoP‐regression group) was calculated and its association with the mode of delivery and duration of different stages of labor was assessed. Results Overall, 469 women were included in the analysis. Among these, 273 (58.2%) had spontaneous vaginal birth, 65 (13.9%) had instrumental delivery and 131 (27.9%) underwent CS. Women in the CS group were older, had narrower AoP at rest and on maximum Valsalva, higher rate of epidural administration and lower 1‐min and 5‐min Apgar scores in comparison with the vaginal‐delivery group. ΔAoP was comparable between the two groups. On Pearson's correlation analysis, AoP at rest and on maximum Valsalva maneuver had a significant negative correlation with the duration of the first stage of labor. ΔAoP showed a significant negative correlation with the duration of the active second stage of labor (Pearson's r, −0.125; P = 0.02). Cox regression model analysis showed that ΔAoP was associated independently with the duration of the active second stage (hazard ratio, 1.014 (95% CI, 1.003–1.025); P = 0.012) after adjusting for maternal age and body mass index. AoP reduction on maximum Valsalva was found in 73 (15.6%) women. In comparison with women who showed no change or an increase in AoP on maximum Valsalva, the AoP‐regression group did not demonstrate significant difference in maternal characteristics, mode of delivery, rate of epidural analgesia, duration of the different stages of labor or rate of NICU admission. Conclusions In nulliparous women at term before the onset of labor, narrower AoP at rest and on maximum Valsalva, reflecting fetal head engagement, is associated with a higher risk of Cesarean delivery. The increase in AoP from rest to Valsalva, reflecting more efficient maternal pushing, is associated with a shorter active second stage of labor. Fetal head regression on maternal pushing is present in about 16% of women and does not appear to have clinical significance. © 2020 International Society of Ultrasound in Obstetrics and Gynecology

Breech progression angle: new feasible and reliable transperineal ultrasound parameter for assessment of fetal breech descent in birth canal

“…A number of studies have demonstrated previously that, even when the fetal head is easily palpable, the reproducibility of digital examination of fetal head engagement is poor [41][42][43][44] . TPU provides a highly reproducible and accurate tool for fetal head descent assessment, and it has high acceptability among women due to its non-invasiveness 22,25,26,[44][45][46][47][48][49][50] . We believe that accurate assessment of fetal breech descent in the birth canal by means of BPA measurement could help in providing more accurate and applicable predictive models of ECV success, although studies are needed to confirm this.…”

The dynamic change of the anteroposterior diameter of the levator hiatus under Valsalva maneuver at term and labor outcome

“…26,27 A very recent study showed that the change in fetal head engagement on maternal pushing as measured by TPU was associated with shorter second stage. 28 The role of the pelvic floor in the fetal engagement is not clear and we encourage future research on this topic.…”

Nomogram based on the final antepartum ultrasound features before delivery for predicting failed spontaneous vaginal delivery in nulliparous women

“…Intrapartum ultrasound has been widely employed as a risk assessment tool for obstetricians to find abnormal labor courses in a noninvasive and objective way (4)(5)(6). With high accuracy, intrapartum ultrasound is a potentially predictive method for women who require OI due to failed SVD (7)(8)(9). However, short time windows in obstetric emergencies limit obstetric preparation (10).…”