What is induction of labour?
Induction of labour is a procedure done to end a pregnancy after 20 completed weeks with the goal being a normal vaginal delivery.
When is induction of labour considered?
Induction is considered when there are complications of pregnancy which means there is risk to the mother or baby’s wellbeing in continuing the pregnancy. The most common indications include high blood pressure (including preeclampsia), PUPPPS, diabetes, cholestatic jaundice of pregnancy, postdates pregnancy, intrauterine foetal growth retardation, unstable foetal lie, twins, a history of a previous very rapid labour, planned VBAC going overdue and to avoid a baby getting too big for an uncomplicated vaginal birth, foetal demise. Sometimes induction is done because of maternal request such as family commitments, husband/partner work commitments, to time arrival of relatives from overseas, excessive pregnancy discomfort, etc.
How is induction done?
Prior to the induction being arranged, I will do a vaginal examination to assess your suitability. In this examination, the dilatation of your cervix, the length of your cervix, how soft your cervix is (‘ripeness’), how low in the pelvis is your baby’s head is (engagement or how far off being engaged) and how well applied your baby’s head is to your cervix.
- If the findings are favourable then you are suitable for induction.
- If the findings are not favourable but induction is technically possible then with ripening of the cervix prior induction can be attempted.
- Sometimes you will be advised because the findings are very unfavourable that it is unlikely the induction process would work and if attempted even with repeated ripening attempts is likely to be associated with a long protracted time induction period before labour is established if it did establish. This would be not only physically and emotionally very draining for you, but also can put your baby at increased risk of foetal dilates. As well especially if you are past your EDC the question needs to be asked why the findings are so unfavourable. Is this an omen of challenges in labour this would mean a Caesarean section because of induction. Careful assessment, discussion and alternatives of management should then be considered.
When is induction done?
This depends on the state of your cervix.
If your cervix not very favourable but induction is possible then Prostin prostaglandin vaginal gel is used to ripen your cervix. A labour ward/birth unit midwife will introduce the gel high into your vagina usually the night prior to the planned induction. You would then stay in the labour ward/birth unit. Your husband/partner is welcome to stay with you. There would be foetal heart rate monitoring prior to and after the gel is introduced for a short period.
Sometimes there is onset of labour after the gel. If this happened there is the possibility you may not need any further intervention.
If your cervix is very favourable or if your baby’s head is very high in your pelvis and is poorly applied to your cervix, or you have an unstable lie then artificial rupture of your membranes (the amniotic sac) (ARM) and sometimes a Syntocinon infusion drip is the safest and most effective option. This will also be required after Prostin ripening of the cervix if you have not gone into labour
Is induction more painful and quicker?
There are stories that induced labours are more painful and too fast. This is not necessarily the case. Everyone’s response is different. Every labour is different. Even every labour for the same person will be different. So to anticipate how a labour would have gone without being induced is impossible to know. Pain thresholds are different. Someone will cope better in one labour than another, and so on. Sometimes it can take hours between the use of Prostin and even an ARM and start of Syntocinon infusion before there is established labour. Sometimes it is quick with there being uterine response sooner. If a Syntocinon infusion is used then the rate is regulated to be optimal for your uterine activity.
Spontaneous labour experiences are also very variable. Many spontaneous labours can be very painful without any intervention in the labour process being done. Some spontaneous labours are very quick, quicker than an induction. Some spontaneous labours are very slow and need help of an ARM and sometimes a Syntocinon infusion.
After Prostin gel and before onset of labour there can be Prostin induction pains as uterine activity increases. Analgesics can be given by the labour ward/birth unit staff if needed
What are the risks of induction?
- Failed induction. This is where induction is attempted and doesn’t work and labour does not establish. This is much more like if induction is attempted when there are very unfavourable findings at vaginal examination. Some pregnant women seeing other obstetricians or as public patients have been subjected terrible experiences with repeated attempts to induce labour over many many hours (sometimes days). This results in significant anxiety and frustration for the woman and her husband/partner and increased risk to their bay and is an omen of a difficult labour and birth. A failed induction will result in a Caesarean section. If very unfavourable then there should be discussion about the necessity for induction on the planned date or whether it can be deferred and other alternatives if delivery is necessary.
- Excessive uterine activity. This is also called ‘uterine hyperstimulation’. While it can happen unexpectedly, it is more likely to occur following Prostin gel insertion if the cervix is very favourable, and with a Syntocinon infusion at an excessive rate. Foetal distress usually occurs as a consequence. That is because there is reduced oxygen getting through to baby when there are excessive uterine contractions. But the foetal distress is only while there is a problem and rarely results in urgent delivery. Once the hyperstimulation has been corrected all is usually ok and the labour can continue as planned.
- Rupture of uterus. If induction of labour is done in a woman with a history of Caesarean section(s), uterine perforation, uterine surgery (such a removal of intermural fibroid(s) or uterine septum) then there is a significant increase in the risk of the uterus tearing apart in labour especially when uterine contractions are stimulated artificially. Overstimulation is particularly dangerous. Uterine rupture is of profound risk to the mother and her baby’s wellbeing. The impact will vary according to the location and the size of the uterine tear, which is unpredictable.
- Newborn problems. There has an association between Syntocinon infusion use and newborn jaundice in some studies though in my experience this is not the case. There are also reports about increased incidence of immature lungs and newborn breathing problems. These can usually be avoided if induction is deferred until EDC or later.