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 labor begins. When successful, version makes it possible for you to try a vaginal birth.
Version is done most often before labor begins, typically around 37 weeks. Version is sometimes used during labor before the amniotic sac has ruptured.
A scheduled cesarean is used to deliver most breech births if a version doesn't work.
To avoid harm to the fetus, a version procedure is closely monitored.
Before the version attempt, you may be given an injection of tocolytic medicine to relax the uterus and prevent uterine contractions. The most commonly used tocolytic medicine is terbutaline.
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 will 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 shown 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 reduce pain associated with the procedure. Epidural anesthesia may increase the success of repeated version attempts.1
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. But version may be more successful if it is 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). A fetus that has engaged 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 if 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.
- The mother has a condition (such as a heart problem) that prevents her from receiving certain tocolytic medicines to prevent uterine contractions.
- A cesarean 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.
- The mother is pregnant with multiple fetuses (twins, triplets, or more).
- The mother's uterus does not have a normal shape.
Version may pose a slight risk of opening a previous C-section scar. Limited research data have shown that women with a cesarean scar have had no such problems. But larger studies are needed to fully assess the risk.2
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%.2 Version is most likely to succeed when:3
- 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 done near term (36 or more completed weeks of pregnancy), before labor starts.
Version is least likely to succeed when:3
- 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.
Compared to the first attempt, repeat version attempts are less likely to be successful.
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 labor, 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. The potential exists for such complications, but they are very rare.
In the rare case that labor begins or the fetus or mother develops a serious problem during version, an emergency cesarean 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. So a pregnant woman with Rh-negative blood is given an Rh immunoglobulin injection (such as RhoGAM) to prevent Rh sensitization, which can cause fetal complications in future pregnancies. To learn more, see the topic Rh Sensitization During Pregnancy.
In rare cases, internal version is used to deliver a second twin or is used during labor 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.
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Klatt TE, Cruikshank DP (2008). Breech, other malpresentations, and umbilical cord complications. In RS Gibbs et al., eds., Danforth's Obstetrics and Gynecology, 10th ed., pp. 400-416. Philadelphia: Lippincott Williams and Wilkins.
American College of Obstetricians and Gynecologists (2000, reaffirmed 2012). External cephalic version. ACOG Practice Bulletin No. 13. Obstetrics and Gynecology, 95(2): 1-7.
Cunningham FG, et al. (2010). Breech presentation and delivery. In Williams Obstetrics, 23rd ed., pp. 527-543. New York: McGraw-Hill.
Primary Medical ReviewerSarah Marshall, MD - Family Medicine
Specialist Medical ReviewerWilliam Gilbert, MD - Maternal and Fetal Medicine
Current as ofNovember 14, 2014