Do we protect the pelvic floor with non-elective cesarean? A study of 3-D/4-D pelvic floor ultrasound immediately after delivery.

Aim: To compare levator defect, loss of tenting, change in biometric measurements of the levator ani and genital hiatus according to the mode of delivery, length of the labor, Bishop score, birthweight and head circumference immediately after delivery.

Methods: One hundred and seventy-one primiparous women who delivered either by vaginal delivery or cesarean were prospectively evaluated. Two 3-D volumes (one at rest, one on Valsalva maneuver) were recorded in the supine position after voiding, and levator biometry, levator defect and loss of tenting were determined on the axial plane.

Results: Of 171 nulliparous women, 84 had vaginal delivery and 87 had cesarean delivery. All hiatal dimensions on resting and maximal Valsalva were found to be higher in the vaginal delivery group. Levator defect rate was found to be significantly higher in the vaginal delivery group (P<0.0001). We found a positive correlation with head circumference, fetal weight and first stage labor length in women who delivered vaginally. In the cesarean delivery group, mean fetal head circumference, fetal weight, length of first stage of labor and Bishop score were higher in women with levator ani defect. Loss of tenting rate was significantly higher in vaginal delivery women (P=0.03).

Conclusion: Labor itself, and factors such as fetal head circumference and fetal weight that cause prolongation of labor, can induce levator ani muscle defect or microtrauma which in turn can cause morphological alterations of the levator hiatus.