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

Abstract

The aim of the present study was to evaluate the correlation between the proportional change of anteroposterior diameter (APD) of levator hiatus from rest to maximum Valsalva maneuver in nulliparous women at term and labor outcome. Methods: We prospectively recruited nulliparous women at term before the onset of labor. Women underwent a two-dimensional transperineal ultrasound, measuring the APD of the levator hiatus at rest and under maximum Valsalva's maneuver. APD change from rest to maximum Valsalva was described both in terms of absolute figures and proportional change. Correlation of APD change with the mode of delivery and with labor durations was assessed. Results: Overall, 486 women were included in the analysis. No significant association between change in APD and the mode of delivery. We found a significant negative correlation between change of APD from rest to Valsalva and the duration of active second stage both in terms of absolute change (Pearson's r = −0.138, P = .009) and in terms of proportional change (Pearson's r = −0.154, P = .004). Survival outcomes based on Cox-regression model showed that APD was independently associated with the duration of active second stage of labor after adjusting for epidural analgesia, maternal age

The maternal pelvic floor and labor outcome

“…Other authors examined the correlation between APD obtained by 2D TPUS at term before the onset of labor and the mode of delivery 20,21,25,26 . Kamel et al included a group of nulliparous women undergoing induction of labor 21 .…”

“…Similarly, Youssef et al did not find a correlation between any of APD measurements at term and the incidence of Cesarean delivery in a group of nulliparous women at term 26 . Recently, Brunelli et al assessed the role of a change in APD with maternal pushing at term before the onset of labor and labor outcome 20 . In their large cohort of 486 nulliparous women, the change in APD from rest to Valsalva did not correlate with the risk of operative delivery (Cesarean or instrumental).…”

“…Over the past years, a number of studies have evaluated the role of the pelvic floor, as assessed by TPUS, on labor outcome [20][21][22][23][24][25][26] . In this manuscript, we will present an overview of current knowledge on the correlation between the female pelvic floor dimensions and function, as assessed by transperineal ultrasound, and the outcome of labor.…”

The usefulness of ultrasound before induction of labor

“…83 Levator hiatus can also be used reliably with volumetric transperineal ultrasound assessment. 84 The levator hiatus can be measured on the axial plane of a three-dimensional acquired volume of the pelvic floor (Figure 8).…”

Intrapartum ultrasound for the management of the active pushing phase

“…Several studies have found a correlation between pelvic floor dimensions, levator ani muscle coactivation at term, and the outcome of labor . [41][42][43] Youssef et al 44 reported the clinical impact of ultrasound evidenced levator ani coactivation and outcome of labor. As levator ani muscle coactivation can be recognized during late pregnancy, the authors concluded that this might be an opportunity to help women to improve their pelvic floor relaxation before the onset of labor.…”