ECV is done by the doctor by placing their hands on the maternal abdomen
External cephalic version (ECV) is usually performed in a labor and delivery unit, with an operating room and resources available to perform emergency cesarean delivery if and when necessary. The fetal and maternal status are continuously monitored. A bedside ultrasound is usually done prior to assessing the fetal position, amniotic fluid level, placenta location, and uterine cavity shape to determine if the procedure can be performed and the expected success rate. Tocolytics (medications to suppress premature labor) and/or regional anesthesia (such as an epidural) may be administered to women who are to undergo ECV. During ECV, the doctor places their hands on the maternal abdomen and gently turns the fetus from breech to cephalic presentation. Ultrasound gel is usually applied over the maternal abdomen to help the doctor’s hand glide easily. If only one doctor is performing ECV, they would place one hand on the fetal head and the other over fetal buttocks and slowly turn the fetus.
If two doctors are performing ECV together, one doctor controls the fetal head, and the other doctor controls the fetal buttocks.
Factors that increase the success rate of ECV include:
- Multiparity (history of more than one pregnancy)
- Non Engagement (non-fixation) of the presenting fetal part into the maternal pelvis
- Relaxed uterus
- Palpable fetal head
- Maternal weight under 65 kg
- Increased amniotic fluid
- Posteriorly lying placenta
- Lateral (right or left sided) lying fetal spine position
- Complete breech fetal presentation
- Gestational age above 36 weeks
- Complete breech presentation
Factors that reduce the success rate of ECV include:
- Nulliparity (first pregnancy)
- Firm maternal abdominal muscles
- Tense uterus
- Anterior (forward) lying placenta
- Decreased amniotic fluid
- Ruptured membranes
- Low fetal birth weight
- Presenting fetal part engaged (fixed) into the maternal pelvis
- Maternal obesity
- Nonpalpable fetal head
- Posteriorly located fetal spine
- Low fetal abdominal circumference below the fifth percentile
What is the external cephalic version?
External cephalic version (ECV) is a procedure in which an attempt is made by the doctor to shift the fetus while still in the uterus. It is done by putting external pressure on the swollen belly. The goal of the procedure is to change the presentation of the fetus from breech to cephalic. ECV is done by the doctor by placing their hands on the maternal abdomen and gently turning the fetus while continuously monitoring the fetus and mother.
Cephalic presentation or vertex presentation is when the head of the fetus is at the uterine mouth at the time of childbirth. The head enters the pelvis first. Cephalic presentation of the fetus is preferred at term because it is associated with lesser risks and mortality to the baby during delivery. Cephalic presentation reduces the need for cesarean delivery.
Breech presentation is when the fetus lies longitudinally, with the buttocks or feet closest to the cervix. Breech presentation occurs in 3-4% of all deliveries. There is an increased risk of perinatal mortality with breech presentation. Fetal death is often associated with fetal malformations, prematurity, and intrauterine death. Hence, more than 90% of breech fetuses are delivered by elective (planned) cesarean delivery. If vaginal delivery is attempted, the doctor may have to convert it to cesarean delivery if the former fails.
Types of breech presentations:
- Frank breech (50-70%): The fetus is in a pike position (the hips are flexed and the knees are extended).
- Complete breech (5-10%): The fetus is in a cannonball position (the hips and knees are flexed).
- Footling or incomplete breech (10-30%): One or both the hips are extended with the foot presenting.
Why is the external cephalic version done?
External cephalic version (ECV) has proven to be a valuable maneuver to reduce the rate of cesarean delivery by reducing the incidence of breech presentation at term. If the patient is an ideal candidate for ECV, the procedure is a safe and effective way to convert fetuses from breech to cephalic presentation to try to avoid cesarean delivery. Cesarean delivery is associated with a high risk of maternal morbidity and mortality. Hence, ECV is usually offered to all near-term women with breech presentation who do not have any contraindications to the procedure to increase their chances of having a safe cephalic vaginal delivery.
When is the external cephalic version not done?
External cephalic version (ECV) is usually contraindicated if the procedure would put the fetus or mother at risk of life-threatening complications or if the procedure is not likely to succeed.
ECV may not be performed in the following conditions:
- Placenta previa (low-lying placenta covering the cervix)
- Abruptio placenta (the placenta detaches from the uterus before delivery)
- Poor fetal health status
- Intrauterine growth restriction (IUGR)
- Abnormal umbilical artery
- Maternal hypertension
- Fetal abnormalities such as neck mass
- History of recent vaginal bleeding during pregnancy
- Anatomical uterine abnormalities
- Uterine pathologies such as uterine fibroids
- Ruptured membranes (referred to as water breaking)
- Hyperextended head of the fetus in the uterus
- Multiple gestations (more than one fetus, such as twins or triplets)
Relative contraindications include:
- Maternal obesity
- A fetus that is small for gestational age
- Oligohydramnios (decreased amniotic fluid in the uterus)
- Uterine scarring from previous cesarean delivery or other surgeries performed to treat uterine pathologies