What is Induction of Labour?
Induction of Labour describes a medical intervention that is performed to initiate labour, rather than waiting for labour to start on its own. Inducing labour can be achieved by using medicine, or by performing a procedure. It is recommended by your healthcare provider when the risks of carrying forward with pregnancy are high, or there are concerns about you or your baby’s health.
Why are inductions performed?
There are various reasons why an induction of labour is recommended.
Some common reasons include:
- Post-term pregnancy (the pregnancy is approaching 7-10 days past your due date)
- Premature rupture of membranes (your water has broken, but labour has not started)
- If the pregnancy becomes complicated in any way, such as chorioamnionitis (infection in your uterus), or there is placental abruption (placenta separates from the uterine wall)
- Fetal concerns such as growth restrictions
Issues with your own health, such as gestational diabetes, or high blood pressure.
Induction of labour is not appropriate if your placenta is blocking the cervix, the baby is breech or transverse, there is active herpes infection, the umbilical cord is in the way, or if there has been major uterine surgery in the past, including a prior Cesaren section with a vertical (classical) incision.
As induction of labour poses some risk, it is usually not performed for social reasons.
How is induction performed?
How an induction is performed depends entirely on the maturity of a cervix. Cervical maturity is determined by examining your cervix and evaluating several features. This includes cervical dilation (how open the cervix is), consistency (soft vs firm), positioning (pointing forward or backward), and effacement (thinness of the cervix). The level of the fetal head gives the healthcare provider further information.
Generally speaking, if the cervix is mature, the induction is easier and takes less time. If the cervix is immature, induction of labour can take a lot longer.
There are different ways to induce labour, and cervical maturity guides the healthcare provider as to which way is best to proceed.
Cervical Ripening – The Immature Cervix
An immature cervix needs to be matured in order to improve the success of induction, and before labour can be started. This can be performed in one of two ways.
Cervidil® is a medicated fabric insert that is placed high into the vagina during a vaginal examination. This medication slowly released medication over 24 hours and helps mature the cervix. Vaginal examinations are performed approximately every 12 hours to determine if the cervix has become mature. On occasion, a second insert is placed after the first 24 hours. Some patients are able to return home on this medication. Once the cervix is mature, you are ready for the next steps for your induction.
The cervix can be alternatively be matured by applying pressure to the cervix. This is referred to as a mechanical dilation, and no medicine is involved. This is accomplished by using a cervical ripening balloon (or alternatively, a Foley catheter). The direct pressure will slowly dilate the cervix and cause it to mature. It is rechecked approximately every 12 hours in much the same way as the Cervidil. If the balloon falls out, it often means that the cervix has dilated and you are ready for the next steps of induction.
Cervical ripening can occur at home if the hospital team feels it is safe to do so. While at home, you will be instructed to return to the hospital if your water breaks, they experience vaginal bleeding, labour starts, or there are decreased fetal movements (< 6 movements in 2 hours). Of course, you should always go to the hospital if you have any concerns.
When the cervix is immature, you should be aware that it can take as long as 1-3 days to have your baby. Maturing the cervix requires patience, as these interventions attempt to accelerate a process that normally takes days to weeks.
The Mature Cervix
If a cervix is mature, either through natural or artificial mean, labour can be initiated immediately. In this scenario, you will be admitted to the labour and delivery unit and monitored until the baby is born.
An artificial rupture of membranes (ARM) is performed by breaking the amniotic sac using a plastic instrument that appears similar to a crochet hook. This is generally painless and is done during a vaginal examination. The baby and your contractions are monitored after the procedure. This procedure may be enough to start your labour.
In many cases, women will need additional help getting into labour and this is achieved using a hormone called oxytocin (also known as Syntocinon or Pitocin) which is administered through an IV. This hormone is made naturally within the body. The hormone is started at a very low dose and incrementally adjusted by small amounts every 30 minutes until contractions are regular and the cervix starts to dilate. You will be placed on a monitor so that your baby and contractions can be monitored the entire time you are receiving this medication.
What are some risks of induction?
All medical interventions pose some risk. Again, induction of labour is recommended when the anticipated risks of carrying forward with pregnancy exceed the risks of induction. The risks of induction include failed induction, fetal heart rate changes, infection, bleeding after delivery, and uterine rupture (rare).
A failed induction is when it is deemed no longer safe to proceed with a vaginal delivery. In this case, a Caesarean section would be recommended. Induction of labour typically increases the risk of Caesarean section by approximately 5%. Approximately 25% of women who proceed with induction will require a Caesarean section (compared with 20% of women who go into labour naturally).
It is important to ask questions and discuss these concerns with your care provider.