Scientific Session 04 — Genitourinary - Reproductive/EndocrineMonday, May 1, 2017
2520. Uterine Position Preconception and Postpartum: An MRI Study
Niemi C1, Reichner T2, Thurmond A3*, Gregory W1 1. University of Wisconsin Madison, Madison, WI; 2. Legacy Mount Hood Medical Center, Gresham, OR; 3. Women's Imaging and Intervention, Lake Oswego, OR
Address correspondence to A. Thurmond (email@example.com)
Objective: The objectives of this study were to describe uterine position as measured by MRI in women before conception and at two intervals postpartum and to determine if change in uterine position occurs after pregnancy.
Materials and Methods: Fifty-two nulliparous women planning pregnancy had a standardized pelvic MRI examination using a 3-T magnet before pregnancy (visit 1), 6 weeks after delivery (visit 2), and 6 months after delivery (visit 3). At all three visits the participant also had an interview including a questionnaire, clinical pelvic examination, transperineal and endoanal 3D ultrasound, and electromyography of the pelvic floor and anal sphincter muscles. Uterine version and flexion were compared between visits. Nine possible positions were noted as the cervix and uterus could each be ante, mid, or retro. Each study was placed into one of the categories on the basis of measured angles of the cervix to vagina (cervical angle) and uterine corpus to cervix (uterine angle). Uterine and cervical angles, bladder volume, and uterine volume were compared between visits. Clinical variables including mode of delivery, gestational age, and fetal weight were analyzed by uterine position categories.
Results: The relative uterine and cervical angles were significantly less anteflexed and anteverted, respectively, at the 6-week postpartum visit compared with the preconception and 6-month postpartum visits. At visit 1, 43 patients (83%) had anteverted anteflexed uteri, compared with 20 (38%) at visit 2 and 34 (65%) at visit 3. Retroflexed uteri were most common at visit 2 (23, or 44%) compared with six (11.5%) at visit 1 and 13 (25%) at visit 3 (p = 0.05). When analyzed in position categories, 27 out of 52 patients experienced a change in position at some point throughout the series of visits. Fourteen of the 27 patients had a change only at the 6-week postpartum visit; 13 (48%) had a different uterine position at the first and last visits. The anteverted, retroflexed position was more common after cesarean delivery compared with vaginal delivery (43% vs 4%, p = 0.005). An overall change in uterine position was not associated with mode of delivery, fetal weight, gestational age, or length of the second stage of labor, and there was no association between bladder or uterine volume and cervical and uterine angles.
Conclusion: We have shown that after delivering a baby, a change in uterine position in the pelvis is common, particularly a change from anteflexion to retroflexion, and that a change to anteversion with retroflexion is associated with cesarean delivery. Pelvic prolapse after delivery remains a puzzle, and this information will be a piece toward hopefully solving that puzzle.