Ultrasonographic and Doppler Evaluation of the Lower Uterine Segment
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- Category: Vol. 77, December 2009
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Ultras ono graphic and Doppler Evaluation of the Lower Uterine Segment in Pregnant Women with Previous Cesarean Section: Correlation with Intraoperative Findings,AKMAL N. EL-MAZNY, NERMEEN A. ABOU-SALEM, HATEM I. ABD EL-MOATY and AHMAD M. EL-HALWAGY
Abstract
Background: The safety of vaginal birth after cesarean (VBAC) has been confirmed in various clinical trials; however, the possibility of uterine rupture exists. With the availability of ultrasonography, assessment of the integrity of the uterine scar has become possible even in a gravid uterus.
Objectives: (1) To compare, by ultrasonography, the appearance of the lower uterine segment (LUS) in pregnant women with previous cesarean section (CS) and women with unscarred uteri. (2) To correlate between ultrasonographic and intraoperative findings in CS cases. (3) To correlate between Doppler and intraoperative findings in CS cases with placenta previa.
Design: Comparative observational cross-sectional study.
Setting: Department of Obstetrics and Gynecology, Kasr El-Aini Hospital, Faculty of Medicine, Cairo University.
Subjects: 200 pregnant women between 36 and 40 weeks’ gestation allocated into two groups: Group A (cases) -100 women with one or more prior CSs, underwent repeat CS without labor trials; and Group B (controls) -100 women without previous CS or uterine surgery.
Methods: The study groups were subjected to transabdom-inal sonography for assessment of LUS thickness and length, and tranvaginal sonography for assessment of LUS thickness and cervical length. The LUS thickness was defined as the shortest distance between chorioamniotic membrane/myo-metrium interface inside and myometrium/urinary bladder wall interface outside. The critical cut-off value for safe LUS thickness, derived from ROC curve, was 2.5 mm. Doppler examination was performed in cases of previous CS with placenta previa.
Main Outcome Measures: The ultrasonographic and Dop-pler findings were correlated to the intraoperative findings.
Results: (1) In CS cases (Group A), the LUS was signif-icantly thinner and non-significantly longer, and the cervix was significantly shorter than in controls (Group B). (2) 15 cases in CS group (Group A) had LUS thickness of !92.5 mm. Intraoperatively; 12 cases (80%) had paper-thin LUS without separation of the muscular layer, and 3 cases (20%) had
dehiscent scar. There were no cases of uterine rupture. (3) 9 cases in CS group (Group A) had placenta previa. Doppler examination revealed diffuse intraplacental lacunae with high velocity flow pattern in 2 cases (22%). Intraoperatively; the 2 cases had placenta accreta and were managed by cesarean hysterectomy.
Conclusion: Ultrasonographic and Doppler evaluation of the LUS was well correlated with intraoperative findings, and may be helpful for an optimally informed obstetrical decision-making regarding management of delivery in women with previous CS.