Breech presentation refers to when the presenting part of the fetus (the lowest part) is the legs and bottom. This is opposed to cephalic presentation, where the head is the presenting part. Breech presentation occurs in less than 5% of pregnancies by 37 weeks gestation.
Types of Breech
- Complete breech, where the legs are fully flexed at the hips and knees
- Incomplete breech, with one leg flexed at the hip and extended at the knee
- Extended breech, also known as frank breech, with both legs flexed at the hip and extended at the knee
- Footling breech, with a foot is presenting through the cervix with the leg extended
Babies that are breech before 36 weeks often turn spontaneously, so no intervention is advised. External cephalic version (ECV) can be used at term (37 weeks) to attempt to turn the fetus.
Where ECV fails, women are given a choice between vaginal delivery and elective caesarean section. Vaginal delivery needs to involve experienced midwives and obstetricians, with access to emergency theatre if required.
Overall, vaginal birth is safer for the mother, and caesarean section is safer for the baby. There is about a 40% chance of requiring an emergency caesarean section when vaginal birth is attempted.
When the first baby in a twin pregnancy is breech, caesarean section is required.
External Cephalic Version
External cephalic version (ECV) is a technique used to attempt to turn a fetus from the breech position to a cephalic position using pressure on the pregnant abdomen. It is about 50% successful.
External cephalic version is used in babies that are breech:
- After 36 weeks for nulliparous women (women that have not previously given birth)
- After 37 weeks in women that have given birth previously
Women are given tocolysis to relax the uterus before the procedure. Tocolysis is with subcutaneous terbutaline. Terbutaline is a beta-agonist similar to salbutamol. It reduces the contractility of the myometrium, making it easier for the baby to turn.
Rhesus-D negative women require anti-D prophylaxis when ECV is performed. A Kleihauer test is used to quantify how much fetal blood is mixed with the maternal blood, to determine the dose of anti-D that is required.
Last updated September 2020