Breech presentation is a type of malpresentation where the fetal head lies over the uterine fundus and the fetal buttocks or feet present over the maternal pelvis, instead of the typical cephalic/head presentation. The incidence of breech presentation in the United Kingdom is 3-4% of all fetuses.
Breech presentation is most commonly idiopathic.
The three types of breech presentation are:
Breech presentation is the most common malpresentation, with a reckoned incidence of around 20% at 28 weeks gestation, 16% at 32 weeks gestation and 3-4% at term. The occurrence is considerably higher in preterm labour. Before 36 weeks, breech presentation is usually asymptomatic and likely to revert to a cephalic position. However, spontaneous version rates for nulliparous women with breech presentation at 36 weeks of gestation are less than 10%.
Risk factors for breech presentation can be divided into maternal, fetal and placental risk factors. Maternal risk factors include multiparity, fibroids, previous breech presentation, and Mullerian duct abnormalities. Fetal risk factors encompass preterm, macrosomia, fetal abnormalities (anencephaly, hydrocephalus, cystic hygroma), and multiple pregnancy. Placental risk factors include placenta praevia, polyhydramnios, oligohydramnios, and amniotic bands.
The typical clinical findings of a breech presentation include a longitudinal lie, head palpated at the fundus, irregular mass over pelvis (feet, legs and buttocks), fetal heart auscultated higher on the maternal abdomen, and palpation of the feet or sacrum at the cervical os during vaginal examination.
Multiple fetal positions exist in breech presentation which are described according to the relation of the fetal sacrum to the maternal pelvis. These are: direct sacroanterior, left sacroanterior, right sacroanterior, direct sacroposterior, right sacroposterior, left sacroposterior, left sacrotransverse and right sacrotranverse.
An ultrasound scan is diagnostic for breech presentation. Growth, amniotic fluid volume, and anatomy should be assessed to check for any abnormalities.
For breech presentation at term, there are three management options with consideration to maternal choice: external cephalic version, vaginal delivery, and Caesarean section.
External cephalic version (ECV) consists of manually rotating the fetus into a cephalic presentation using pressure against the mother's abdomen under ultrasound guidance. Entonox and subcutaneous terbutaline are used to relax the uterus.
ECV has a 40% success rate among primiparous women and a 60% success rate among multiparous women. It should be offered to nulliparous women at 36 weeks and multiparous women at 37 weeks gestation.
If ECV does not succeed, delivery options include elective caesarean section or vaginal delivery.
Contraindications for External Cephalic Version include: Antepartum haemorrhage, ruptured membranes, previous caesarean section, major uterine abnormality, multiple pregnancy and abnormal cardiotocography (CTG).
Vaginal delivery is an option, but carries risks such as head entrapment, birth asphyxia, intracranial haemorrhage, perinatal mortality, cord prolapse and fetal and/or maternal trauma.
When feasible, delivery should be performed without traction and with an anterior sacrum in order to reduce the risk of fetal head entrapment. An epidural may be offered to the mother, as vaginal breech delivery can be very painful.
Contraindications for vaginal delivery in a breech presentation include footling breech, macrosomia (usually defined as larger than 3800g), growth restricted baby (usually defined as smaller than 2000g), other complications of vaginal birth, lack of clinical staff trained in vaginal breech delivery, and previous caesarean section.
A caesarian section booked as an elective procedure at term is the most common management for breech presentation. This option is preferred for preterm babies (due to an increased head to abdominal circumference ratio at preterm) and if External Cephalic Version is unsuccessful or if that is the mother's preference. Caesarean section has fewer risks than vaginal delivery.
Fetal complications of breech presentation include developmental dysplasia of the hip (DDH), cord prolapse, fetal head entrapment, birth asphyxia, intracranial haemorrhage and perinatal mortality.
Complications of external cephalic version include transient fetal heart abnormalities (common), fetomaternal haemorrhage and placenta praevia.
Breech presentation is a situation where the fetus is not in a cephalic presentation for delivery. There are three types of breech presentation: complete, incomplete and frank breech. The most common clinical findings include: longitudinal lie, smooth fetal head-shape at the fundus, irregular masses over the pelvis and abnormal placement being required for fetal hear auscultation. The diagnostic investigation is an ultrasound scan. Breech presentation can be managed in three ways: external cephalic version, vaginal delivery or elective caesarean section. Complications are more common in vaginal delivery, such as cord prolapse, fetal head entrapment, intracranial haemorrhage and birth asphyxia.
