Sonographic imaging of cervical scars after Cesarean section.
OBJECTIVE
To investigate whether uterine contractions at the time of a Cesarean section have an impact on future presence and location of a cervical Cesarean scar.


METHODS
A targeted transvaginal ultrasound examination of the fetus, uterus and cervix was done in 2973 consecutive women at 14-16 weeks' gestation. The sonographer was blinded to the women's previous obstetric histories. The presence and location of a sonographic cervical hypoechogenic line, which probably represented a Cesarean scar, was recorded.


RESULTS
There were 180 women with a previous Cesarean section performed before the start of uterine contractions and 173 with a Cesarean section performed during contractions in labor. The cervical hypoechogenic line was more common in sections performed during contractions (75.7% vs. 52.7%; P < 0.001) and was more distally located from the internal os (17.9 +/- 9.4 vs. 14.6 +/- 9.1 mm; P = 0.01). A hypoechogenic line was observed in 21/2620 women without a previous Cesarean section, representing a false-positive rate of 0.8%.


CONCLUSIONS
Cesarean sections, especially those done during uterine contractions, are actually performed through cervical tissue. This finding is in agreement with the physiological process of cervical effacement during contractions.
Zimmer
E Z
EZ
Department of Obstetrics and Gynecology, Technion - Israel Institute of Technology, Haifa, Israel. ALKOL@netvision.net.il
Bardin
R
R
Tamir
A
A
Bronshtein
M
M
D002584:Cervix Uteri / Q000000981:diagnostic imaging; D002585:Cesarean Section; D017604:Cesarean Section, Repeat; D002921:Cicatrix / Q000000981:diagnostic imaging* / Q000209:etiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D007747:Labor Stage, First; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal; D014590:Uterine Contraction; D014599:Uterus / Q000000981:diagnostic imaging; D016064:Vaginal Birth after Cesarean