
Induction in Labour
Induction of labour has become an ever increasing fact of life. Regardless of whether you believe social inductions to be good or bad, for some couples, timing of delivery is every bit as important as a medical induction. I care for many women whose partners are overseas. For them, induction of labour was the only way DAD would see the baby before it was 6 months old.- Medical Induction
- Social Induction
- Method of Induction
- Prostaglandins
- What to Expect
- ARM
- Syntocinon
- Strip & Stretch
- Complications
Labour is induced if there is more risk in allowing the pregnancy to continue than there is in earlier delivery. Situations where this might occur include:
- High Blood Pressure
- Intrauterine Growth Restriction (Placental Insufficiency)
- Diabetes requiring Insulin
- Prolonged Pregnancy
- For those women who get to 40 weeks plus 7-10 days, I routinely offer induction to avoid the danger of stillbirth which occurs more frequently after this time.
Why would a woman want to be induced? Their reasons vary and most have thought through the process before making their request.
I have had occasions when the husband is only going to be in town for 48 hours around the expected due date. Timing becomes essential. Other women may have previously had an extremely rapid labour and are in danger of delivering in the car on the way to hospital.
Method of Induction: Before discussing the different methods used to induce labour, it is important to distinguish the induction from the labour. Medical people talk about an: -
- Induction to Labour Interval - This is the time taken to establish you in labour and may vary from 5 minutes to 5 days (poetic license) being a failed induction.
- Labour to Delivery Interval - This is the time taken from when you are diagnosed in labour to when you deliver. It should really be no different in an induced labour to a spontaneous labour.
Here I will only be discussing the Induction process: -
Prostaglandin: This is perhaps the most popular method of induction used by Obstetricians. PROSTIN (prostaglandin) comes as a gel (1mg or 2mg) which is inserted in the vagina, near the cervix. It acts by stimulating the normal cascade of chemicals required to initiate normal labour.
PRO’S:
- Easy - a quick vaginal examination and its done
- Works for 90% of women
- Although most women do respond, this may take from 5 minutes to 5 days or not at all
- Unpredictable response
I use the lowest dose of gel in order to reduce the risk of hyper stimulation. This can lead to very strong contractions, coming too frequently and too close together. Foetal distress can result from these severe contractions and a caesarean section may need to be done.
You are reviewed around 1pm and if you are contracting, then the fore waters may be ruptured to facilitate the process of labour. This is not always necessary but can speed things up.
If not responding, a further 1mg dose is inserted with review planned for 5 pm. At 5pm, if there has been no response then you are faced with a decision:
- either go home, as most people will return in labour in the next 24 hours or
- Have a caesarean section for a failed induction. Obviously a caesarean section is indicated if the induction was performed on medical grounds because the baby needs to come out.
ARM (Artificial Rupture of Membranes): Simply performing an ARM can be enough to stimulate labour for some women.
This is done by performing a vaginal examination and passing a small hook through the cervix. This hook then makes a hole in the membranes, "breaking the waters". Once the membranes have ruptured, the barrier to infection is gone and you are really committed to delivery.
If an ARM is performed a few hours after priming the cervix with Prostin, it usually augments the process of induction or labour, making it more efficient.
Syntocinon: In some situations Syntocinon will be used for induction of labour.
This is usually done by performing an ARM and then commencing an intra-venous infusion of Syntocinon. This is similar to Oxytocin, a chemical produced in normal labour that stimulates uterine contractions. The dose of the drug is gradually increased until regular contractions are occurring. This means 2-4 contractions every 10 minutes. Unlike some (but not all) spontaneous labours, your contractions will get painful fairly quickly. This may not allow you to gradually get used to the pain and is a reason why epidurals are more common with this type of induction. I guess it is a bit like Samboys, the flavour really hits you.
Syntocinon is also used to AUGMENT a labour which is progressing slowly.
Once contractions reach a satisfactory level in terms of frequency and strength, the infusion is maintained at that level until delivery.
Strip and Stretch: A simple, minimally invasive procedure can be performed by your Obstetrician to help "move things along". This is known as "stirring the waters" or a "strip and stretch".
Using sterile gloves the Obstetrician introduces a finger through the cervix (if possible) and sweeps the membranes off the inner aspect of the cervix. This helps release the bodies own prostaglandins which can stimulate labour. It is especially effective for women who have had babies before and have a partly dilated cervix. Like all things, nothing is guaranteed. It should not be done if the placenta is low lying / praevia.
Complications: 95% of inductions will work and the woman will establish in labour. This does not mean that there will be a vaginal delivery.
Successful induction is usually dependent on a number of factors:
- Favourable cervix (soft, stretchy, open)
- Application of the head to the cervix (a high head is bad news)
- Parity (if you've done it before that's better)
- Gestation (the later the better)
- Method (chosen based on the above)
- For some women, induction does not work and my policy is not to force it.
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