MR imaging of pubic symphysis after uncomplicated vaginal delivery and planned caesarean delivery in the first postpartum week.

PURPOSE: To compare changes in the pubic symphysis between women with vaginal delivery and women with caesarean sections within the first postpartum week.

MATERIALS AND METHODS: After institutional review board approval 30 healthy women were prospectively examined with MRI (transverse STIR-sequence) three days after delivery. 17 women with vaginal delivery (mean age 33.2 ± 4 years) and 13 with caesarean delivery (35.2 ± 5.6 years) were compared by two musculoskeletal radiologists. Bone marrow edema (location and extent), fluid in the joint gap, joint space width and stress fractures were assessed.

RESULTS: Prevalence of bone marrow edema was high and not different between groups (13/17 (76.5%) vaginal deliveries) and 10/13 (76.9% caesarean deliveries) for reader 1 (p = 0.992) and 14/17 (82.4%) and 10/13 (76.9%) for reader 2 (p = 0.762). Size of bone marrow edema was not statistically significantly different for both readers (results reader 1: right side 2.5 ± 3.3 mm vs. 6.3 ± 7.3 mm, p = 0.300; left side 3.4 ± 4.1 mm vs. 4.1 ± 4.6 mm, p = 0.837). Fluid in the joint was seen in 4/17 (23.5%) vs. 2/13 (15.4%) (p = 0.580) for reader 1 (similar for reader 2). Joint space width did not differ between groups (2.6 ± 0.7 mm vs. 3.1 ± 1.2 mm, p = 0.198). Pubic symphysis diastasis (joint space width > 10 mm) was not observed. Interreader agreement for these parameters was substantial to almost perfect (0.671-0.984, kappa values/intraclass correlation). Reader 1 found no stress fractures, while reader 2 suspected 1 stress fracture on a right pubic bone in a woman after caesarean delivery.

CONCLUSIONS: Pubic bone marrow edema is present in 3 of 4 women in the first postpartum week unrelated to the delivery mode.