Clinical importance of appearance of cesarean hysterotomy scar at transvaginal ultrasonography in nonpregnant women.

OBJECTIVE: To estimate the association between the appearance of cesarean hysterotomy scars at transvaginal ultrasound examination of nonpregnant women and the outcome of subsequent pregnancies and deliveries. METHODS: A total of 162 women who had ever given birth by cesarean underwent transvaginal ultrasound examination of the hysterotomy scar 6 to 9 months after the latest cesarean delivery. Published ultrasound definitions of large scar defects were used. The appearance of the hysterotomy scar at ultrasound examination was compared with the outcome of subsequent pregnancies and deliveries. Clinical information on subsequent pregnancies was obtained from medical records. RESULTS: Six women were lost to follow-up, leaving 156 for analysis. Of these 156 women, 69 became pregnant after the ultrasound examination (99 pregnancies, 65 deliveries). There were no placental complications or scar pregnancies. At the first repeat cesarean delivery after the ultrasound examination, 5.3% (1/19) of the women with an intact scar or a small scar defect had uterine dehiscence or rupture compared with 42.9% (3/7) of those with a large defect (P=.047), odds ratio 11.8 (95% confidence interval 0.7-746). CONCLUSION: Our results point toward a likely association between large defects in the hysterotomy scar after cesarean delivery detected by transvaginal ultrasonography in nonpregnant women and uterine rupture or dehiscence in subsequent pregnancy. (Obstet Gynecol 2011;117:525-32) DOI:10.1097/AOG.0b013e318209abf0