External Cephalic Version
External cephalic version is a procedure that can help turn a baby from a breech position to a head-down position before birth, potentially allowing for a vaginal delivery instead of a cesarean section.
Table of contents
- What is External Cephalic Version?
- When is ECV Needed?
- When is the Procedure Done?
- How the Procedure Works
- When ECV is Not Recommended
- Benefits and Risks
- Success Rates and What Happens Next
What is External Cephalic Version?
External cephalic version, often called ECV or EV, is a procedure healthcare providers use to turn a baby from a breech position to a head-down position while the baby is still inside the mother’s uterus. The procedure is done by applying firm pressure to the outside of the mother’s abdomen, without placing hands inside the vagina.[1]
A breech presentation means that the baby is positioned with their buttocks, feet, or both pointing down toward the vagina instead of being head-down. This position can make vaginal delivery more complicated and often leads to a cesarean section.[3]
The goal of ECV is to increase the chances of having a vaginal birth by rotating the baby into the ideal head-down position. With the global cesarean section rate reaching 34%, fetal malpresentation ranks as the third most common indication for cesarean delivery, accounting for nearly 17% of cases.[2]
When is ECV Needed?
A breech position is common throughout most of pregnancy. Almost one-fourth of all babies are in a breech presentation at 28 weeks of pregnancy. However, at around 36 weeks of pregnancy, most babies naturally turn so they are in a head-down position. About 3 to 4 out of every 100 babies remain in a breech position after 36 weeks.[2]
Several factors may contribute to a baby being in a breech presentation. These include having been pregnant before, carrying twins or more, having too much or too little amniotic fluid (the liquid that surrounds and supports the baby in the womb), an abnormally shaped uterus, fibroids (growths in the uterus), or placenta previa (when the placenta covers the opening of the uterus). However, most babies in a breech presentation are otherwise completely normal.[3]
There are three main types of breech presentation. An extended or frank breech occurs when the baby is bottom first, with the thighs against the chest and feet up by the ears. Most breech babies are in this position. A flexed breech means the baby is bottom first, with the thighs against the chest and the knees bent. A footling breech occurs when the baby’s foot or feet are below the bottom.[5]
When is the Procedure Done?
Healthcare providers typically recommend attempting ECV at around 37 weeks of pregnancy, though fetal presentation should be assessed beginning at 36 weeks.[1] It is preferable to wait until term before external version is attempted because of an increased success rate and to avoid preterm delivery if complications arise.[4]
By 37 weeks, if spontaneous version is going to occur, it is likely to have already happened. Waiting until this time also reduces the risk of the baby turning back to a breech position after a successful ECV.[13]
Depending on the situation, ECV can be successfully performed later in pregnancy, and some studies show that ECV during delivery admission has a 65% success rate.[13]
How the Procedure Works
Before the procedure begins, healthcare providers will use ultrasound (a test that uses sound waves to create pictures) to confirm the baby’s position, check the location of the placenta, and assess the amount of amniotic fluid. The baby’s heart rate is also checked with fetal monitoring before and after ECV.[3]
The procedure is typically performed near an operating room in a hospital setting. This is important because if any problems arise, a cesarean delivery can be performed quickly if necessary. The whole procedure may take about two hours, including the time to check the baby before and after.[1]
During ECV, the healthcare provider places their hands on the mother’s belly and applies firm pressure to turn the baby into a head-down position. The baby is manipulated by a forward roll or back flip, encouraging them to do a “somersault” and turn over. This pressure lasts several minutes and can cause the uterus to cramp.[1] Two people may be needed to perform the procedure.[3]
Many healthcare providers give medicine to relax the uterus, which can make it easier to turn the baby. One commonly used medication is salbutamol, which is injected under the skin. This medicine relaxes the muscles in the uterus. Mothers may notice their heart starts to beat faster after receiving this medicine, but this is not dangerous and usually stops after about 3 minutes.[5] Studies show that medications like terbutaline have doubled the rate of ECV success.[13]
Some healthcare providers also offer pain medication, but this is optional. Many women feel some discomfort when pressure is applied to the belly, but the level of pain varies from person to person.[1]
If the procedure is unsuccessful, it can be reattempted at a later time.[4]
When ECV is Not Recommended
ECV is not suitable for everyone. Healthcare providers will check medical history to determine if the procedure is safe. ECV will not be tried if vaginal delivery is not clinically appropriate for other reasons.[3]
Certain factors may make ECV unsafe or not recommended. These include having low amniotic fluid, having had vaginal bleeding, carrying twins or more, abnormal fetal heart rate, placenta previa, an irregularly shaped uterus, high blood pressure, diabetes, or needing a cesarean section for another reason.[1]
Other situations where ECV may not be appropriate include if the placenta has come away from the wall of the uterus (placental abruption), certain abnormalities of the reproductive system, or if the mother has a condition that prevents taking medications to stop contractions.[3]
ECV can be considered in some cases if the mother has had a previous cesarean delivery, though this requires careful individual evaluation.[3] There are no absolute contraindications, and each case should be evaluated individually.[13]
Benefits and Risks
The main benefit of ECV is that it can increase the chances of having a safe and successful vaginal delivery. Breech pregnancies are not dangerous until it is time for delivery. If a woman wants to deliver vaginally, turning a breech baby through ECV might be the best chance at having the childbirth she planned.[1]
Studies show that ECV leads to fewer cesarean deliveries and lower odds of complications such as endometritis (infection of the uterus lining), sepsis (a serious infection throughout the body), and hospital stays longer than 7 days. There are also lower hospital charges. No differences have been found for low Apgar scores, low umbilical vein pH, or neonatal death.[13]
Routine use of external version could reduce the rate of cesarean delivery by about two thirds, making it a cost-effective intervention in the management of breech babies at term.[4]
While ECV is generally safe, there are some risks. The most common risk is changes in the baby’s heart rate. Typically, the heart rate stabilizes when the procedure is discontinued.[13]
Overall, serious adverse effects are very low, with rates less than 1%. Possible complications include premature rupture of the membranes, placental abruption, preterm labor, fetal distress, vaginal bleeding, umbilical cord prolapse, stillbirth, and fetomaternal hemorrhage.[1]
Although the chance of complications is low, cesarean delivery services should still be readily available during the procedure. However, the rate of cesarean deliveries due to complications from ECV is low.[13]
Yes, ECV can make a woman go into labor. This is another reason why ECV procedures typically happen near an operating room.[1]
Success Rates and What Happens Next
The overall success rate for ECV is approximately 58% to 60%, meaning a little more than half of all ECVs will result in the baby being turned to a head-down position.[1] Some studies report success rates as high as 63 to 65%.[4]
Several factors affect the success of ECV. There is a positive association between having had previous pregnancies (parity) and successful version. Babies in a transverse or oblique position are associated with higher immediate success rates. Lower success rates occur at hospitals with higher cesarean rates.[13]
Factors that might predict success include amniotic fluid volume, location of the placenta, and maternal weight. Factors associated with failure include this being a first pregnancy, advanced dilation, fetal weight less than 2500 grams, an anterior placenta, and low station.[13]
If ECV is successful, the baby remains in the head-down position and vaginal delivery can proceed as planned. However, some babies who are successfully turned move back into a breech presentation. If this happens, the procedure can sometimes be attempted again.[3]
If ECV does not work and the baby stays breech, the woman will most likely have a cesarean section. Some healthcare providers may be comfortable delivering a breech baby through the vagina, depending on their expertise and the mother’s health history and pregnancy. Women should speak with their healthcare provider about delivery options if ECV does not work, as other methods to encourage the baby to turn may be recommended.[1]
