True rupture/scar dehiscence in delivery following prior section

Abstract

Fear of uterine rupture has led to the widespread practice of 'Once a section, always a section'. Between 1972 and 1982, 1498 patients with one or more previous cesarean sections were delivered at University College Hospital, Galway. Trial of labor was undertaken in 844 patients, while the remaining 654 patients underwent repeat elective section because they had two or more prior sections. Eight true ruptures and 22 scar dehiscences were found. Regional analgesia and oxytocin did not significantly affect the rate of true rupture. The mean parity with uterine rupture was five, and it occurred most frequently in the initial trial of labor. There were four perinatal deaths associated with true rupture. Failure to detect the already compromised fetus before labor and delivery, rather than the method of delivery, was responsible for fetal demise in some instances. Five true ruptures were found in the trial of labor group (i.e. a ratio of 1:169), with the loss of three babies. A further baby was stillborn in a mother who ruptured a classical scar before labor. There were no maternal deaths in trial-of-labor patients and one in the elective section group. Two patients with true rupture had their uterus repaired, and were subsequently delivered by section. Another two patients with bloodless dehiscence and no repair, had two subsequent elective repeat sections each, and the unrepaired scar dehiscence was not evident.

The Relationship Between Gestational Age and the Incidence of Classical Caesarean Section

“…Repeat Caesarean section is mandatory after a CCS due to an incidence of uterine rupture in future pregnancies of 2-8% (compared to 0.5% for LUSCS) (1,5,6). Not all cases of uterine rupture after CCS will be prevented by repeat elective Caesarean section since rupture of the classical scar can occur prior to elective Caesarean section, either antenatally (as with 1 of the women in this study) or in early labour before Caesarean section can be effected (7)(8)(9).…”

Cesarean section scar evaluation by saline contrast sonohysterography

“…We realize that many questions remain unanswered, the main one being: is it safe for a woman in whom a dehiscence has been found to become pregnant? Some authors have suggested the surgical correction of the uterine scar21, 22, but no proof of its necessity or utility has been found. The prevalence of scar dehiscence (in the present series 2/33 or 6%) is much higher than the reported risk of uterine rupture (0.4%)7.…”

Detection of scar dehiscence at delivery in women with prior cesarean section

“…Labor and vaginal delivery are usually not affected by lower segment 'window' ( 3 ) . Meehan et al ( 5 ) reported two patients with bloodless, unrepaired dehiscence who had subsequent elective cesareans with no evidence of scar dehiscence. Although elective repeated cesarean delivery is recommended, vaginal delivery has been reported after nonrepair of such lower segment separation (8).…”

“…Obstetrical management policy allowed each patient with one previous lower uterine segment scar a trial of labor, except when there were indications for a repeat cesarean section. Trial of labor was defined as induced or spontaneous labor in a patient with prior cesarean section (5). Induction and stimulation methods used in labor were artificial rupture of membranes and breast stimulation.…”

“…The preponderance of medical literature traditionally advocates routine postpartum transcervical revision of the uterine scar following vaginal delivery in patients with a prior cesarean section, in order to explore the possibility of dehiscence (1,2,5,9,10). However, uterine defects are rare, and their management is controversial (3), so that the salutary value of the procedure is doubtful.…”