Imaging after cesarean delivery: acute and chronic complications.

Cesarean delivery is a commonly performed operation and accounts for nearly one-third of all births in the United States. Although it is a safe procedure, cesarean delivery has a variety of acute and chronic complications that prompt imaging with ultrasonography (US), computed tomography, and magnetic resonance imaging. Acute complications include hematomas in specific locations that are unique to the procedure, as well as a variety of infections. A bladder flap hematoma occurs in the space between the bladder and the lower uterine segment, whereas a subfascial hematoma is an extraperitoneal collection located in the prevesical space posterior to the rectus muscles and anterior to the peritoneum. Puerperal infections after cesarean delivery include abscesses, wound infections and dehiscence, uterine dehiscence and rupture, and pelvic thrombophlebitis. The prevalence of chronic complications related to the healed cesarean delivery scar is unknown, but the scar may result in technical limitations for pelvic US due to the adhesions between the anterior lower uterine segment and the anterior abdominal wall. The cesarean delivery scar also leaves the patient susceptible to several unique diagnoses. A cesarean scar "niche" is a tethering of the endometrium that can serve as a reservoir for intermenstrual blood and fluid. Intrauterine devices can be malpositioned in the cesarean delivery scar, and endometrial implants can develop in the abdominal wall years after surgery. These patients are also at increased risk for implantation abnormalities including cesarean scar ectopic pregnancy, retained products of conception, and placenta accreta. Familiarity with the normal postoperative findings following cesarean delivery is necessary to recognize acute and chronic complications, which are being encountered with increasing frequency. © RSNA, 2012.