Studies concerning the use of a transcervical Foley catheter for cervical ripening and induction of labor in women with a prior cesarean delivery are limited (Ben-Aroya, 2002; Jozwiak, 2014). In a retrospective study of 2479 women with prior cesarean delivery, the uterine rupture risk using a transcervical Foley catheter for labor induction (1.6 percent) was not significantly greater than that with spontaneous labor (1.1 percent) or with using amniotomy with or without oxytocin (1.2 percent) (Bujold, 2004). In contrast, Hofman (2004) described 138 women who underwent preinduction cervical ripening with a Foley catheter compared with 536 women who entered labor spontaneously. They observed a significant and inordinately high uterine rupture risk during labor following Foley catheter cervical ripening compared with spontaneous onset of labor-6.5 versus 1.9 percent.
Concerns that epidural analgesia for labor might mask the pain of uterine rupture have not been veriied. Fewer than 10 percent of women with scar separation experience pain and bleeding, and fetal heart rate decel erations are the most likely sign (ieser, 2002). That said, Cahill and coworkers (2010a) documented that more frequent episodes of epidural dosing were associated with increasing uterine rupture rates.
VBAC rates are similar, and in some cases higher, among women with labor epidural analgesia compared with those using other forms of analgesia (Aviram,
Following VBAC, some clinicians routinely document the integrity of a prior scar by placing a hand through the dilated cervix and along the inner surface of the lower uterine segment. But routine uterine exploration is considered by others to be unnecessary. In a longitudinal study of 3469 women who had a VBAC, seven uterine dehiscences and one uterine rupture yielded an overall event rate of 0.23 percent (Silberstein, 1998). They concluded that trans cervical evaluation need only be performed in symptomatic patients.
Currently, the benefits of routine scar evaluation in the asymptomatic woman are unclear, however, surgical correction of a dehiscence is necessary if significant bleeding is encountered. Our practice is to routinely examine these prior hysterotomy sites. Any decision for laparotomy and repair takes into consideration the extent of the tear, whether the peritoneal cavity has been entered, and the presence of active bleeding.
Progress of labor in women attempting TOLAC is similar to normal labor, and no speciic pattern presages uterine rupture (Graseck, 2012; Harper, 2012b; Sondgeroth, 2017). Before hypovolemic shock develops, symptoms and physical findings in women with uterine rupture may appear bizarre unless the possibility is kept in mind. For example, hemoperitoneum from a ruptured uterus may result in diaphragmatic irritation with pain referred to the chest. This may direct one to a diagnosis of pulmonary or amnionic fluid embolism instead of uterine rupture. As shown in Figure 31-5, the most common sign of uterine rupture is a nonreassuring fetl heart rate pattern with variable decelerations that may evolve into late decelerations and bradycardia. In 36 cases of such rupture during TOLAC, there were fetal signs of uterine rupture in 24, maternal signs in eight, and a combination of maternal and fetal in three (Holmgren, 2012). Few women experience cessation of contractions following uterine rupture, and the use of intrauterine pressure catheters does not assist reliably in the diagnosis (Rodriguez, 1989).