Pelvic floor changes in the first term pregnancy and postpartum period

To follow a prospective cohort of women during their first term pregnancy to elucidate the nature and timing of changes to the pelvic floor during pregnancy and after vaginal delivery.

Enrolled subjects were evaluated at four time points with dynamic MRI, POP-Q examinations, and validated symptom questionnaires. The four assessments occurred during the first trimester (ePG), late third trimester (lPG), within a week after vaginal delivery (ePP), and three months postpartum (lPP). Two-dimensional T1-weighted MRI measurements included bladder descent and area of the levator hiatus at rest and during Valsalva maneuvers. Sample size of ten subjects was calculated for a power of 0.8 to detect a 20% change in bladder position with p < 0.05. Comparative statistical tests were used for parametric and non-parametric data, respectively.

Twelve subjects completed the study. At lPP, the bladder descent was increased (p = 0.03) at rest and with Valsalva compared to ePG. Levator hiatus area did not differ (p = 0.63) between time points at rest or with Valsalva. Median POP stage increased (p = 0.001) to 1.5 at lPP. Mean genital hiatus increased (p = 0.0003) at each time point. Higher scores were recorded on the UDI-6 (p < 0.001) and the PFDI-20 (p = 0.003) questionnaires at lPG and ePP, but returned to ePG levels by lPP.

Anatomic changes measured by dynamic MRI and POP-Q examinations demonstrate significant descent at 3 months postpartum. However, these anatomic changes did not significantly correlate with changes in symptoms.