What are the indications and contraindications to external cephalic version (ECV)?
What are the success rates of ECV?
What are the key steps to the procedure?
What are the risks associated with ECV?
Mrs. Smith is a 27-y.o. G2P0010 at 37 0/7 weeks gestation who was sent to you by her primary obstetrician for ECV after discovery of breech presentation at her 36-week appointment. The patient has many questions regarding the intended procedure, and as the OB/GYN hospitalist who will be performing the ECV, you must be prepared to answer her.
Malpresentation (i.e. noncephalic presentation) complicates approximately 5% of pregnancies at term.1 Diagnosis is typically made by ultrasound, preferably before the onset of labor. Although abdominal palpation or vaginal exam may suggest malpresentation, the diagnosis should be confirmed by ultrasound. The American College of Obstetricians and Gynecologists (ACOG) recommends documentation of fetal presentation starting at 36 weeks gestation.2 If malpresentation is identified and no contraindications exist, the obstetrician should offer the patient ECV and counsel her on the risks and benefits of the procedure. In ECV, the obstetrician attempts to turn the fetus manually into a cephalic presentation. ACOG has recently published a Practice Bulletin that summarizes the major points and evidence with regard to ECV.2
ANATOMY, PHYSIOLOGY, AND PATHOPHYSIOLOGY
Breech presentation occurs in 3% to 4% of labors.1 It is more common earlier in gestation, with 25% of pregnancies <28 weeks and 7% of pregnancies at 32 weeks being complicated by breech presentation.1 There are three types of breech presentation: frank, complete, and incomplete (also known as footling) (Fig. 63-1). Factors associated with breech presentation include such fetal malformations as trisomies, prematurity, müllerian anomalies, and fundal placentation.1 As experience with breech vaginal deliveries (Chapter 59) is declining, most women with a breech fetus deliver by cesarean section (C-section) (Chapter 60). Alternatively, ECV may be employed to turn the fetus and permit a vaginal delivery. Of note, ECV also should be offered in cases of transverse and oblique lies, and it has a higher success rate in these circumstances than in breech presentation.2
Types of Breech Presentation. A. Complete breech. B. Frank breech. C. Incomplete, or footling breech. (Reproduced with permission from Posner G, Dy J, Black A, et al: Oxorn-Foote Human Labor & Birth, 6th ed. New York, NY: McGraw-Hill Companies, Inc; 2013.)
All women with singleton fetuses in nonvertex presentations at term should be offered a trial of ECV unless contraindications exist. Box 63-1 lists the indications for ECV.
Box 63-1 Indications for ECV
Singleton intrauterine pregnancy with malpresentation
No contraindication to vaginal delivery (e.g. placenta previa)
≥ 37 0/7 weeks gestation, determined by reliable dating