What happens when your baby is breech?

What does it mean if your baby is in the breech position by the time you're about to give birth? Dr Emma Parry explains.

Whenever your doctor or midwife feels your tummy, she is trying to find out more about your baby. First her size - is your baby growing well or is she too small or too big? Next, which way is the baby is lying - head pointing towards the birth canal, bottom pointing down or baby lying across the uterus. If a baby is coming bottom first this is known as a breech presentation.

In the second trimester (13-26 weeks) babies are often breech as the baby is small in comparison with the uterus and has a lot of amniotic fluid to swim in. It is also often difficult to tell which way around the baby is lying and it may even change position during the examination.

In the third trimester, the baby gets a lot bigger and the amount of amniotic fluid reduces. The shape of the uterus usually encourages the baby to turn upside down so her head comes out first. The fundus (top of the uterus under your ribs) is wider than the part just above the pelvis. The baby's bottom and legs are together bigger than the head and so usually settle at the top. By 32 weeks 75% of babies are cephalic (head first). By 37 weeks only 3-4% of babies are not cephalic.

It is rare for a baby to be transverse (across the uterus) at term (37 to 42 weeks), and there are often factors contributing to this, such as excess amniotic fluid, fibroids obstructing the pelvis, or a very relaxed and large uterus (after lots of babies!).

Are all breech babies the same? It goes without saying that every baby is an individual. However, breech presentation can be divided into three broad categories:

• Flexed leg breech - the baby has her legs crossed.
  
• Extended leg breech - the baby is a future gymnast and has her legs straight in front with the feet by the ears.
  
• Footling breech   - the baby has one or both feet down below her bottom "dancing on the cervix".
  

Cause and consequence

In most cases there is no particular reason why a baby is breech presentation at term, but there are a couple of instances that would make it more likely. If labour starts pre-term or there is rupture of the membranes pre-term the baby may well be breech. Another reason may be extra fluid around the baby, which could be due to diabetes or the baby having a bowel blockage, or the baby not swallowing due to  a muscle movement problem.

For a healthy normal baby who is breech at term there are  a few options women need to consider. The main options are:

• External cephalic version
  
• Vaginal breech delivery
• Caesarean section

Each case will be different and it is important that each woman discusses the issues and her preference with her Lead Maternity Carer (LMC). If the LMC is a midwife or GP, then a referral to an obstetrician will be made.

The obstetrician will arrange for an ultrasound scan to confirm the baby is breech and the type of breech (flexed, extended or footling). In addition, she'll get information on the estimated weight of the baby and the amount of fluid.

External cephalic version (ECV)

A common approach when Mum and baby are healthy is to attempt an ECV in the hope of avoiding interventions during birth such as epidural and monitoring, as well as reducing the risk to the baby of cord prolapse and head entrapment during birth.  Cord prolapse is when the umbilical cord slides through the open cervix into the vagina ahead of the baby and gets squashed. The baby's oxygen supply is cut off and an emergency C-section is needed.

External (outside) cephalic (head first) version (to convert) pretty much does what it says. During this procedure the obstetrician uses her hands on the mum's abdomen to push and pull the baby from a breech presentation to a cephalic presentation. It usually takes around fve to 10 minutes and often takes up to three attempts. It's performed in a hospital, and the woman is awake with no pain relief as this has been shown to be the safest way to do the procedure. It is uncomfortable, but usually not painful - and I can say that from experience!

An ECV is usually done at 36-37 weeks. Before this there is still a good chance the baby will do the decent thing and turn head first by herself. After 37 weeks the baby gets more settled and the chance of successfully turning the baby reduces.

An ECV is usually done in a unit with access to a theatre in case an emergency C-section is required. Often a drug is given to relax the uterus and this has been shown to increase the success rate. The baby is monitored by a heart trace before and after, as well as by ultrasound scan during the procedure.The main complications are:

• Rupture of membranes and the early onset of labour.
  
• Cord entanglement (this might lead to a C-section).
  
• Bleeding from the placenta.
  

These conditions are rare but they're why the procedure is done in hospital.

The success rate varies from centre to centre and between individual obstetricians. The usual figure quoted is between 40 and 60%. If it's a flexed breech or if a woman has had babies before the success rate increases. If the baby is successfully turned to cephalic, about 4% will turn back to breech. These babies are just plain awkward!

Large studies have shown that using ECV reduces the C-section rate for breech babies and most midwives and obstetricians strongly recommend it when there are no other concerns.

Getting that baby out

If an ECV isn't possible or doesn't work then you need to decide the best way to deliver the baby. Twenty years ago the standard approach was to aim for a vaginal delivery. Some women still opt for a vaginal breech delivery now, but not many.

If a woman is planning a breech birth, the best position for the baby is flexed or extended. This means that the part of the baby coming first creates a nice seal up against the cervix as it dilates. In this situation the labour progresses well and minimises the risk of cord prolapse. In the case of footling breech, a C-section is recommended, as there is a high risk of cord prolapse.

It is usually expected that the labour will start spontaneously, with no induction, and that it will progress normally without the need to intervene with medications to increase contractions. Most obstetricians, however, will recommend an epidural to allow a C-section if needed and if help is required to deliver the baby vaginally.

During labour it is usual to monitor the baby's heart rate continuously. Once Mum reaches the pushing stage and the buttocks are starting to appear, Mum's legs are usually put in leg supports and the bottom of the bed removed. This allows baby's body to hang down once it is delivered and naturally assists the baby's head into the pelvis.

At this stage the obstetrician will use gentle push and pull, with the woman pushing to deliver the head. Sometimes forceps are needed to guide the baby's head out. There is a risk at this stage that the head will be too big and get stuck.  But if a good assessment beforehand, it's a rare complication.

The other option is to go straight to a C-section and not even attempt a vaginal breech birth, an increasingly popular option as outcomes from C-sections have steadily improved.

A Canadian study 10 years ago randomly allocated participants to either an attempted vaginal delivery or a planned C-section. Researchers found babies in the vaginal birth group had a one in 20 chance of serious long-term problems or death, compared with one in 75 in the C-section group. This result means many women and obstetricians no longer want to consider a vaginal breech birth.

Most obstetricians will recommend a C-section to a woman who has a breech presentation baby at term if ECV has not been successful or possible.

Dr Emma Parry is a specialist obstetrician and gynaecologist, Clinical Director of Maternal-Foetal Medicine at Auckland Hospital and spokesperson for the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG).