Dynamic 3T Pelvic Floor Magnetic Resonance Imaging in Women Progressing from the Nulligravid to the Primiparous State

Introduction And Hypothesis: The objective was to prospectively characterize dynamic pelvic 3-Tesla magnetic resonance imaging (dp3T MRI) findings in nulligravida women and characterize changes 6 months after delivery in the same woman.

Methods: In this prospective study, nulligravida women seeking assisted reproductive technology for pregnancy were recruited. After physical examination by Pelvic Organ Prolapse Quantification (POP-Q), Brink assessment and measures including the Pelvic Floor Distress Inventory-20 and Pelvic Floor Impact Questionnaire-7, pre-pregnancy dp3T MRI at rest, with strain, and evacuation were performed. Assessments were repeated ≥6 months postpartum. Analysis included Welch and paired t tests for continuous variables, Fisher's exact test for differences in categorical outcomes, and paired t tests for postpartum symptoms.

Results: Nineteen subjects (mean ± SD age, 31 ± 5 years) completed baseline clinical and dp3T MRI studies, 15 delivered and 10 (30.5 ± 3 years) completed pre-pregnancy and post-delivery clinical and dp3T MRI assessments. There were no significant changes in scores of validated questionnaires (all p > 0.05) or on POP-Q measures post-delivery. Two (20%) subjects without pre-pregnancy levator tears had tears on MRI post-delivery. MRI measures of pelvic organ descent were increased post-delivery. Seventeen pelvic soft-tissue parameters increased by greater than 10% post-delivery, including 5 out of 70 (7.1%), 17 out of 110 (15.5%), and 50 out of 110 (45.5%) values exceeding thresholds at rest, strain, and evacuation respectively.

Conclusions: Dynamic pelvic 3T MRI detected levator tears and increased pelvic organ descent, which can be directly attributed to pregnancy and delivery.