Approximately 2 of every 10 women will have a levator ani injury during their first vaginal delivery1. A number of ante- and intrapartum risk factors for levator trauma and irreversible overdistension of the levator hiatus have been described. Obstetric factors that are associated with levator trauma include large fetal head circumference, forceps assisted vaginal delivery, prolonged second stage of labor 1,2,3,4. There is a five fold increase in the odds of pelvic organ prolapse (POP) five to 10 years following a vaginal delivery compared to cesarean section 5. Levator ani deficiency severity is associated with clinically significant prolapse 7. Fifty five percent of women with POP have visible major levator ani muscle damage compared to 15% of women with normal support, making it the strongest known factor to be associated with both vaginal birth and POP 8. Consequently, multiple studies have shown that pelvic floor weakness occurs following childbirth, which then is a risk factor for the development of pelvic floor disorders. This effect seems to impact women more often following a vaginal delivery, compared to a cesarean delivery 9. To date, no studies have compared the association between pelvic floor strength and postpartum pelvic dysfunction when comparing high and low risk obstetric populations.

Objective: To examine the association between pelvic floor strength and pelvic floor dysfunction after the first vaginal delivery in low-risk vs. high-risk obstetric populations.

This is a single-site retrospective cohort study of patients undergoing their first vaginal delivery and were recruited between the years 2012 and 2020 at a large university hospital’s Obstetric and Gynecology Department (Oklahoma Health Sciences Center). Women were classified as high risk if they had a 2nd degree or greater perineal laceration or any previously defined risk factors for LA injury at vaginal birth (including prolonged second stage of labor >160 min, instrumented delivery, or fetal head circumference >35.5cm). Women were classified as low risk if they had an intact perineum and no previously defined risk factors for LA injury at vaginal birth.

Relevant obstetric information was obtained by chart abstraction. At the 6 week visit, a history was obtained, and an exam was performed using the pelvic organ prolapse quantification system (POP-Q). Levator ani strength was measured using the Peritron™ perineometer. Vaginal closure force (in cmH20) was measured at both rest and during maximal voluntary contraction. Patients also completed PFIQ-20 and PFDI-7 questionnaires at 3 months postpartum, and this data was recorded.

Data analysis is currently ongoing. The goal for this project is to be completed by next spring.