external verson

External cephalic verson

External cephalic version is a process by which a breech baby can sometimes be turned from buttocks or foot first to head first. It should only be attempted from 34 weeks on and often is reserved for later because breech presentation greatly decreases with every week.

External verson is a non surgical method in which a doctor can help move the baby within the uterus. A medication to help relax the uterus might be given as well as an ultrasound exam, to better check the position of the baby, the location of the placenta, and the amount of amniotic fluid in the uterus. Gentle pushing on the lower abdomen can turn the baby into the head-down position. Throughout the external version, the baby's heartbeat will be checked closely so that if any problems should occur, the health care provider will stop turning immediately. Most attempts at external version are successful; however, as the due date gets closer this procedureis more difficult.

In this procedure hands are placed on the mother's abdomen around the baby. The baby is moved up and away from the pelvis and gently turned in several steps from breech, to a sideways position, and finally to a head first presentation. In any attempt to move the baby should be encouraged to keep its knees pulled in so as not to further complicate things.

As with any procedure there can be complications most of which can be greatly decreased by having an experienced professional on the birth team. An ultrasound to estimate a sufficient amount of amniotic fluid and monitoring of the fetus immediately after the procedure can also help minimize risks.

There are a few cases in which there can be a greater risk, these include pre-eclampsia, uterine scarring, and multiple pregnancies or fetal abnormality.

External Cephalic VersionANDREW S. COCO, M.D., M.S., and STEPHANIE D. SILVERMAN, M.D.

Lancaster General Hospital, Lancaster, Pennsylvania

A patient information handout on external cephalic version, written by the authors of this article, is provided on page 744.

External cephalic version is a procedure that externally rotates the fetus from a breech presentation to a vertex presentation. External version has made a resurgence in the past 15 years because of a strong safety record and a success rate of about 65 percent. Before the resurgence of the use of external version, the only choices for breech delivery were cesarean section or a trial of labor. It is preferable to wait until term (37 weeks of gestation) before external version is attempted because of an increased success rate and avoidance of preterm delivery if complications arise. After the fetal head is gently disengaged, the fetus is manipulated by a forward roll or back flip. If unsuccessful, the version can be reattempted at a later time. The procedure should only be performed in a facility equipped for emergency cesarean section. The use of external cephalic version can produce considerable cost savings in the management of the breech fetus at term. It is a skill easily acquired by family physicians and should be a routine part of obstetric practice.

The incidence of breech presentation at term is about 4 percent.1 Multiple factors may cause a fetus to present breech instead of vertex, including placenta previa, multiple gestation, uterine anomalies, fetal anomalies, poor uterine tone and prematurity. The majority of cases have no apparent cause. Physicians performing external cephalic version (also referred to as external version) externally rotate the fetus from a breech presentation to a vertex presentation. Over the past 15 years, external cephalic version has become a valuable, although underused, option in the management of the breech fetus at term.

The most important reason to wait until the fetus is at term is to avoid iatrogenic prematurity if complications arise.

Before the resurgence of the use of external cephalic

version, management of breech presentation consisted of either routine cesarean delivery or a selected trial of labor. However, over the past two decades, theoretically for safety concerns regarding the fetus, the rate of cesarean delivery for breech presentation increased from 14 percent in 1970 to the current rate of up to 100 percent at some institutions.2 Very few trials of labor are being attempted. Approximately 12 percent of cesarean deliveries in the United States are performed for breech presentation. Breech presentation ranks as the third most frequent

indication for cesarean section, following previous cesarean section and labor dystocia.3 Routine use of external version could reduce the rate of cesarean delivery by about two thirds.4

This article reviews the rationale for the use of external version and its technical aspects, including the currently accepted protocol and manual maneuvers, factors predicting success and cost-effectiveness.

History of External Cephalic Version

TABLE 1

Selection Criteria for Vaginal Breech Delivery

Estimated fetal weight from 2,000 to 4,000 g (4 lb, 6 oz to 8 lb, 13 oz)

Frank or complete breech presentation

Flexed fetal head

No major fetal anomalies or placenta previa on ultrasound

Adequate magnetic resonance, computed tomography or x-ray pelvimetry

Reprinted with permission from Eller DP, Van Dorsten JP. Breech presentation. Curr Opin Obstet Gynecol 1993;5:664-8.

External version has a

pparently been practiced since the time of

Aristotle (384 to 322 b.c.), who stated tha

t many of his fellow authors advised midwiv

es who were confronted with a breech presen

tation to "change the figure and place the

head so that it may present at birth." Howe

ver, external version eventually fell out o

f favor as a result of several concerns: it

s high rate of spontaneous reversion (turni

ng back to breech presentation) if performe

d before 36 weeks of gestation, possible fe

tal complications, and the assumption that

an external version converts only those fet

uses to vertex that would have converted sp

ontaneously anyway.

The rebirth of the use

of external version occurred in the early

1980s in the United States, after a protoco

l developed in Berlin was replicated with f

avorable results in several U.S. studies.5

,

6

Consumer demands for more nonintervention

al birth experiences also played a role in

its resurgence. Currently, external version

is performed in many institutions, and the

procedure is taught in most obstetric resi

dency programs and in some family practice

residency programs.

The safety of vaginal b

reech delivery has been a longstanding cont

roversy. In a recent retrospective study,7

investigators found that the risk of fetal

morbidity and mortality is increased when v

aginal delivery is attempted and concluded

that cesarean section should be recommended

routinely. In another study,8

however, inv

estigators reached an opposite conclusion.

They calculated a corrected perinatal morta

lity of zero based on a series of 316 women

undergoing a trial of labor.

Other studie

s have documented the success and safety of

external version. The authors of a recent

literature review4

of 25 studies on the eff

icacy of external cephalic version calculat

ed an overall success rate of 63.3 percent,

with a range of 48 to 77 percent. Most of

these studies used the currently accepted p

rotocol that is discussed in this article.

These studies documented minimal risks, inc

luding umbilical cord entanglement, abrupti

o placenta, preterm labor, premature ruptur

e of the membranes (PROM) and severe matern

al discomfort. Overall complication rates h

ave ranged from about 1 to 2 percent since

1979.4

In another study,9

fetal heart rate

changes occurred in 39 percent of fetuses d

uring external version attempts, but these

changes were transient and had no relations

hip to the final outcome. Importantly, the

literature provides overwhelmingly reassuri

ng evidence regarding the risk of fetal dea

th. Before 1980, four fetal deaths from ext

ernal cephalic version had been reported. A

ll of these deaths occurred in association

with attempts at external version using gen

eral anesthesia.1

0

Since 1980, only two fet

al deaths have been reported with external

version. Both occurred without the use of f

etal heart rate monitoring or ultrasonograp

hy in preterm infants in Zimbabwe.1

1

A rece

nt study1

2

reported a success rate for exte

rnal cephalic version of 69.5 percent. Note

worthy was the fact that among fetuses unde

rgoing successful version, the incidence of

intrapartum cesarean section was 16.9 perc

ent, a figure that was 2.25 times higher th

an that in the control group. The high rate

of cesarean delivery resulted from a signi

ficantly higher incidence of fetal distress

and labor dystocia in the group receiving

external version. Results of this study dem

onstrate that even after successful version

, a higher rate of intrapartum abnormalitie

s may occur.

Algorithm for external cephalic version.

Prospe

ctive, randomized trials regarding vaginal

breech delivery are not available and are u

nlikely to be carried out because of liabil

ity concerns. A consensus in the obstetric

literature is lacking, and the optimal rate

of cesarean section is likely to remain el

usive and controversial. A policy of routin

e cesarean section eliminates the fetal ris

ks, but considerably increases the risks of

maternal morbidity. Neither option address

es the primary problem of the breech presen

tation, which the external version can answ

er in selected situations.

First, the degree of engagement of the presenting part should be determined and gentle disengagement performed if possible.

Sele

ction cri

teria for a safe attempt at vaginal breech delivery are listed in Table 113

When these cri

teria are applied, approximately 70 percent of women with a vaginal breech presenta

tion will be candidates for attempted vaginal delivery. Of these, approximately two thir

ds will have a successful delivery.If inclusion criteria are routinely used, the calculated

success rate for vaginal delivery of a fetus in the breech position is just over 40 percent.

Or, conversely, about 60 percent of fetuses presenting in the breech position will be deliv

ered by cesarean section despite optimal attempts to achieve a vaginal delivery.

Not only

does external cephalic version significantly reduce the number of breech presentations

at term, its use also reduces the high rate of cesarean delivery for this indication. Any

reduction in the primary rate of cesarean delivery has an additive effect on the overall ra

te by decreasing the number of women undergoing repeat cesarean delivery. The maj

or benefits of external cephalic version are reduced maternal morbidity and mortality fro

m surgery.

Timing of Breech Version at Term

Figure 2. The breech should be mobilized. This may require a second person to vaginally disengage the breech.