inducing labour
If labour doesn't start naturally after a 'sweep', you will be offered an induced labour at hospital

Dr Asma Khalil, consultant obstetrician and fetal medicine specialist at The Portland Hospital, discusses inducing labour

One of the most joyous moments in any mother’s life is the day she welcomes her child into the world, and while usually the little one will make an appearance on its own, on occasions where the estimated time frame is exceeded and you’re approaching 42 weeks, your obstetrician or midwife may recommend inducing labour. Every year, one in five labours is induced, so knowing what to expect from this common procedure is important.

How is induced labour different to ‘natural’ labour?

Induced labour is generally known as the process of using medications or natural methods to help kick-start the process.

When labour starts naturally, the hormone prostaglandin is released in the muscle wall of your womb. Later on in labour, your brain releases a second hormone, called oxytocin. Both of these stimulate the contractions in the uterus.

The advice during an induced labour is that baby should be monitored more closely. This is partly because if too much hormone is given, it can make the contractions happen too close together, and this could make the baby unhappy. It’s also because the underlying reason for the induction may put baby at increased risk of becoming unhappy when regular contractions start (whether they had started naturally or not), so it’s important to have an obstetrician or midwife on hand.

Why would I need to have an induction?

An induction will be recommended if a pregnancy runs a couple of weeks past the due date. When women go past the 42-week mark, it is more common for the placenta to ‘run down’ and not give the baby as much food and oxygen as it needs.

Additionally, if there is a chance that other medical conditions may present harm to either the mother or the baby, your doctor may advise that labour is induced. Common reasons include high blood pressure in the mother (known as pre-eclampsia), reduced fetal movements, diabetes, or issues relating to the baby’s development and size.

Ahead of an induced labour, your doctor will discuss the advantages and disadvantages with you. They will also help to determine the safest way to continue with the delivery, and advise you on the best course of action. I always stress that receiving an induction is a personal choice, however when there is a medical reason, such as high blood pressure, it’s usually pretty obvious that inducing labour is much safer for both you and the baby.

Are there any risks?

Labour induction is not always successful. If attempts to get the labour started have been going on for 24 hours or more and there’s still no sign of labour, the doctors will discuss your options with you. If all is well with you and your baby, there may be time to take a break for a further 24 hours, then try again. If there isn’t time to wait – for example, if high blood pressure is becoming increasingly difficult to control, the only remaining option may be a caesarean section.

What does the induction process involve?

A membrane sweep or ‘cervical sweep’ may be offered before labour is induced. This involves a vaginal examination and an attempt to separate the membranes in your uterus away from the cervix. This may release your natural prostaglandin hormones to help start labour. The sweep can be a bit uncomfortable but usually only takes a minute or two. Unfortunately, it’s not that successful; it only increases the chances of going into labour in the next 48 hours a little. But if there’s time, it’s worth a try.

If labour doesn’t start after this, or if there isn’t time to try a sweep, you will be offered induction of labour, which will take place at a hospital maternity unit. As a first step, the baby’s heartbeat will be monitored for 10 or 15 minutes to make sure baby is completely happy before giving any hormones.

A vaginal examination will take place before the mother is administered a hormone-like substance called prostaglandin. This is very much like your own natural prostaglandin hormone that your womb releases when labour starts naturally. It does two things: it acts to ‘ripen’ your cervix, or in other words, makes your cervix softer and more elastic, so when the contractions come, it’s more ready to dilate. These hormones can also gradually bring on contractions. Usually, you will be given either a tablet, pessary or gel containing this hormone. Over the next few hours you may experience period-like pains, or contractions, or you may feel nothing at all. Depending on which type of prostaglandin has been used (gel, tablet or pessary), this may be repeated after six hours or so. This is sometimes all that is needed to induce labour, and at some point the contractions will start to come regularly and your cervix will dilate.

Sometimes, however, as the hormone wears off, the contractions may also reduce or even stop. In this situation, if your midwife finds that your cervix is already a little open (as a result of the contractions), she may suggest breaking your waters. This is done during a vaginal examination and usually takes a minute or two. As the water comes out, it can help to stimulate some of your own natural prostaglandin hormones and get the contractions started again.

If, a few hours after the waters have broken there is still no sign of the contractions returning, the midwife or doctor may suggest giving you a second hormone – oxytocin. Although this is a synthetic hormone, it is actually identical to your own natural oxytocin. This is given via a drip in your arm. It’s started off at a very low level and increased in small steps every 10 to 15 minutes until the contractions are coming every three minutes or so (which is what you would expect in normal labour).

The oxytocin drip almost always makes the contractions come. But it’s not safe to use until the waters have broken (either naturally or by the doctor). And it’s not possible to break the waters until the midwife can get to them, in other words, your cervix is open a little. So it’s typical to go through the steps in the order above. Some women will need just the prostaglandin, some will need that and their waters broken, and some will need all three. Other options include doctors using a Foley catheter or cervical ripening balloons; these can help to induce labour and are particularly useful when hormones must be avoided.

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