ECV should be carried out in an area that has ready access to a facility equipped to perform emergency cesarean delivery (American College of Obstetricians and Gynecologists, 20 16a). Because of the risk for surgical intervention, intravenous access is obtained, and patients abstain from eating for 6 or more hours. Sonographic examination is performed to conirm nonvertex presentation, document amnionic fluid volume adequacy, exclude obvious fetal anomalies if not done previously, and identiy placental location and fetal spine orientation. Preprocedural external monitoring is performed to assess fetal heart rate reactivity. Anti-D immune globulin is given to Rh-D negative women. Tocolysis and regional analgesia may be elected, and rationale for these is provided in subsequent sections.
he woman is placed in left lateral tilt to aid utero placental perfusion, and Trendelenburg positioning helps during elevation of the breech. During the procedure, we prefer to monitor fetal heart motion sonographically. An abundant abdominal coating of ultrasound gel permits this and also minimizes painful skin friction (Vallikkannu, 2014).
A forward roll of the fetus usually is attempted first. One or two providers may participate, and one hand grasps the head. he fetal buttocks are then elevated from the maternal pelvis and displaced laterally (Fig. 28-15). The buttocks are then gently guided toward the fundus, while the head is simultaneously directed toward the pelvis. If the forward roll is unsuccessful, a backward flip is attempted. ECV attempts are discontinued for excessive discomfort, persistently abnormal fetal heart rate, or after multiple failed attempts. Failure is not always absolute. Ben-Meir and colleagues (2007) reported a spontaneous version rate of 7 percent among 226 failed versions-2 percent among nulliparas and 13 percent among multiparas.
If ECV is successful, a nons tress test is repeated until a normal test result is obtained. If version is completed before 39 weeks' gestation, then awaiting spontaneous labor and fetal maturity is preferred. In some studies, immediate labor induction is linked to higher cesarean delivery rates (Burgos, 2015; Kuppens, 2013).
FIGURE 28-15 External cephalic version. With an attempted forward roll, clockwise pressure is exerted against the fetal poles.
To relax the uterus prior to an ECV attempt, existing evidence supports the use of tocolysis (American College of Obstetricians and Gynecologists, 2016a). Most data support the use of the beta-mimetics terbutaline and ritodrine (Cluver, 2015). In one such trial, Fernandez and coworkers (1996) reported that the success rate with subcutaneous terbutaline-52 percentwas significantly higher than without-27 percent. Our policy at Parkland Hospital is to administer 250 I1g of terbutaline subcutaneously to most women before attempted ECV. When maternal tachycardia-a known side efect of terbutaline-is noted, the attempt is begun. Data are limited and, in some cases nonsupportive, for alternate agents that include calciumchannel blockers, such as nifedipine; nitric oxide donors, such as nitroglycerin; the oxytocin-receptor antagonist atosiban; and another betamimetic salbutamol (Burgos, 2010; Hilton, 2009; Kok, 2008; Vani, 2009; Velzel, 2017; Wilcox, 2011).