Treatment Overview
External cephalic version, or version, is a procedure used to turn
a fetus from a
breech position or side-lying (transverse) position
into a head-down (vertex) position before labour begins. When successful,
version makes it possible for you to try a vaginal birth.
Version is done most often before labour begins, generally
around 36-37 weeks. Version is sometimes used during labour before the
amniotic sac has ruptured. This can be a good time to
use version, when labour is constantly monitored and a
caesarean delivery (C-section) can be done right away
if necessary. But, the chance to do the version can be lost if labour speeds up
or the amniotic sac ruptures.
A scheduled caesarean is used to deliver most breech births.1 However, trying a version at 36 or more completed weeks of
pregnancy may increase your chances of being able to deliver vaginally.2
Fetal monitoring
To avoid harm to the fetus, a version procedure is closely
monitored.
- Fetal
ultrasound is first used to confirm the fetus's position, where the
placenta is, and the amount of
amniotic fluid. Fetal ultrasound is often used during
the version attempt to monitor the fetal position.
- Electronic fetal heart monitoring is used before,
possibly during, and after a version attempt. An active
fetus whose heart rate increases normally with movement is usually considered
to be healthy. If the fetus's heart rate becomes abnormal, the version
procedure may be stopped.
Version procedure
Before the version attempt, you may be given an injection of
tocolytic medication to relax the uterus and prevent
uterine contractions. The most commonly used tocolytic medication is
terbutaline (such as Bricanyl).
While the uterus is relaxed, your doctor will attempt to turn the
fetus. With both hands on the surface of your abdomen—one by the fetus's head
and the other by the buttocks—the doctor pushes and rolls the fetus to a
head-down position. You may feel discomfort during a version procedure,
especially if it causes the uterus to contract. The amount of discomfort
depends on how sensitive your abdomen is and how hard the doctor presses on
your abdomen during the version attempt. If your fetus appears to be in
distress, as indicated by a sudden drop in heart rate, the procedure is
stopped.
If a first attempt at version is not successful in turning the
fetus, your doctor may suggest another attempt, possibly with
epidural anesthesia to help you relax and to decrease
pain associated with the procedure. Studies suggest that epidural anesthesia
increases the success of repeated version attempts.3, 4
Serious complications are rare during
external cephalic version. But they do happen. This is why a version
is performed in a hospital where you can have
an emergency C-section delivery if
needed.
What To Expect After Treatment
You and your fetus may be monitored for a short time after a
version attempt. You can resume your normal activities after the procedure is
over.
Why It Is Done
Version may be attempted when:
- The mother is 36 to 42 weeks pregnant. Before
36 weeks, a fetus is likely to turn back into a head-down position on its own.
However, version may be more successful if done as early as possible after 36
weeks because the fetus is smaller and is surrounded by more amniotic fluid and
space to move in the uterus.
- The mother is pregnant with only one
fetus.
- The fetus has not dropped into the pelvis (has not engaged).
Once engaged, a fetus is very difficult to move.
- There is enough
amniotic fluid surrounding the fetus for turning the
fetus. If the amount of amniotic fluid is below normal (oligohydramnios), the
fetus is more likely to be injured during a version attempt.
- The
mother has been pregnant before. A previous pregnancy usually means that the
wall of the abdomen is more flexible and can stretch during a version attempt.
Version may also be attempted when the mother has not been pregnant
before.
- The fetus is in the
frank,
complete breech, or footling breech
position.
Version is usually not done when:
- The bag of waters (amniotic sac)
has ruptured.
- A mother has a condition (such as a heart problem)
that prevents her from receiving certain tocolytic medications to prevent
uterine contractions.
- A
caesarean delivery is needed, such as when
the placenta partially or completely covers the cervix (placenta
previa) or has separated from the wall of the uterus (placenta
abruptio).
- Fetal monitoring shows that
the fetus may not be doing well.
- The fetus has
a hyperextended head. This means that the neck is straight, rather than bending
the head forward with the chin tucked into the
chest.
- The fetus is known or suspected to have a birth
defect.
- A mother is pregnant with multiple fetuses (twins,
triplets, or more).
- A mother's uterus is not normally
shaped.
Version may pose a slight risk of opening a previous C-section
scar. Limited research data have shown that women with a caesarean scar have had
no such problems. But larger studies are necessary to fully assess the
risk.5
In some cases, a doctor will choose not to try a version
when there is less
amniotic fluid than normal (oligohydramnios)
around the fetus.
How Well It Works
External cephalic version has an average success rate of
58%.5 Version is most likely to succeed when:6, 2
- The mother has already had at least one
pregnancy and childbirth.
- The fetus, or a foot or leg, has not
dropped down into the pelvis (has not engaged).
- The fetus is
surrounded by a normal amount of amniotic
fluid.
- The procedure is performed at term (36 or more completed
weeks of pregnancy), before labour starts.
Version is least likely to succeed when:6
- The fetus is engaged down in the mother's
pelvis.
- The doctor cannot grasp the fetal head.
- The
uterus is hard or tense to the touch.
About 4% of fetuses return to a breech position after a successful
version.2
Compared to the first attempt, repeat version attempts are less likely to be successful.
Risks
With frequent monitoring, the risks of external cephalic version to
the mother and fetus are low.
Potential risks of version, for which the fetus and mother are
closely monitored, include:
- Twisting or squeezing of the
umbilical cord, reducing blood flow and oxygen to the
fetus.
- The beginning of labour, which can be caused by rupture of
the
amniotic sac around the fetus (premature rupture of
the membranes, or PROM).
- Placenta abruptio, rupture of the uterus, or damage to
the umbilical cord. While the potential exists for such complications, they are
very rare.
On the rare occasion that labour begins or the fetus or mother
develops a serious problem during version, an emergency caesarean section
(C-section) may be done to deliver the fetus.
What To Think About
Version has a very small risk for causing bleeding that could lead
to mixing of the blood of the mother and fetus. Therefore, a pregnant woman
with
Rh-negative blood is given an Rh
immune globulin injection (such as WinRho) to prevent
Rh sensitization, which can cause fetal complications
in future pregnancies. For more information, see the topic Rh Sensitization
During Pregnancy.
Rarely, internal version is used to deliver a second twin, or
during labour when an emergency threatens the life of the fetus. In such a case,
a doctor tries to turn the fetus by reaching into the uterus.
Complete the
special treatment information form (PDF)
(What is a PDF document?)
to help you understand this treatment.