Sonography of the low transverse incision, cesarean section: a prospective study.

Using sonography, the uterine incision site was prospectively studied in 36 asymptomatic patients, two days after cesarean section. The findings were compared with those seen in 21 symptomatic, postcesarean patients. In the asymptomatic patients, the incision site was visualized as an oval symmetric region of distinct echogenicity interposed between the lower uterine segment and the posterior wall of the urinary bladder. In eight of the 36 asymptomatic patients, a small (less than 1.5 cm) round hypoechoic mass was present in or adjacent to the uterine incision and distinct from the normal incision. These probably represented insignificant hematomas. Of the 21 symptomatic patients, 17 had either a subfascial hematoma, a bladder-flap hematoma, or endometritis. Two were sonographically normal, and one showed a hematoma in the paracolic gutter. In the remaining patient, there was a 5-mm asymmetrically placed hypoechoic mass representing an insignificant hematoma. Significant bladder-flap hematomas were characteristically round, greater than 2 cm masses asymmetrically placed in or adjacent to the uterine incision. Using sonography, the normal appearance of the lower uterine incision can be distinguished from significant hematomas.