Breech: the types and how it happens
How common is breech presentation?
Towards the end of pregnancy, the overwhelming majority of babies will be lying in the womb with the head as the leading part. This is called "cephalic presentation".
Less than 5 per cent or one in twenty have the bottom as the leading part at this stage and this is what is known as breech presentation.
What about breech earlier on in pregnancy?
The leading part is of no significance in the first half of pregnancy and normally it would not be sought for.
At around 24 weeks of gestation, approximately a third of all fetuses (33%) will be found to be in breech presentation; the figure drops to about 15 per cent by 30 weeks and is 4-5 per cent at 37 weeks. Without intervention, it is said to be even lower (2-3%) at forty weeks.
It is therefore quite obvious that most babies will be leading with the head at term, regardless of the position earlier on in pregnancy.
Remember, ‘Term’ refers to the period of pregnancy after 37 weeks of gestation.
What are the predisposing factors for breech presentation at Term?
In many cases, no explanation can be found for the baby's persisting breech presentation. However, there are some known predisposing factors that make some women more prone to have a baby presenting with breech.
Uterine (womb) abnormalities
Presence of masses or tumours in the pelvis, such as fibroids and ovarian cysts
Excessive or reduced amniotic fluid.
Are there different types of breech presentation?
Yes. The mother will often hear her doctor or midwife describing the type of breech that the fetus is in.
The least common breech presentation is what is known as ‘complete breech’ (or flexed breech). In this type, the baby is in a sitting position and both the hips and knees are flexed (squatting).
The second type is ‘footling breech’ where a foot is leading just below the baby's buttocks. Very rarely, both feet may extend below the buttocks.
The most common type of breech is ‘frank breech’ (extended breech), where the knees are extended and therefore the legs lie alongside the body, with the feet adjacent to the baby's head.