Induced labour and membrane sweeps: reasons, benefits and drawbacks

Most labours (99 in 100) begin by 42 weeks of pregnancy. However, induction is increasingly common in the UK. NHS data shows that 29 in 100 labours were induced in 2022-2023 (NHS Digital, 2023).

What is induction of labour?

Induction of labour is when the mother or birthing parent agrees to have labour started artificially by midwives or doctors. It takes place in a hospital antenatal ward or labour ward (NHS, 2023).

In late pregnancy, information about induction of labour is provided by the midwife at a regular antenatal appointment. There should be time to think and ask questions before making a decision (NICE, 2021). 

The timing of any proposed induction will depend on:

• the mother or birthing person's age 
• their health 
• how the pregnancy is going 

If the preference is to wait for labour to begin, expectant management will be offered. This means the mother or birthing parent and baby will be monitored more frequently by the midwife or doctor (NICE, 2021).  

How does monitoring happen?

Monitoring happens at additional hospital appointments, where the mother or birthing parent has cardiotocography (CTG) for around 30 minutes.  

This involves an elastic belt around the belly holding two flat plates against the abdomen. These record the baby’s heartbeat and any contractions. If there are no signs for concern, it is possible to go home. Monitoring might happen daily, or every other day.

What are the other options?

Some women and birthing people prefer not to have either induction or expectant management. The options then are to:

• wait without additional monitoring 
• plan a caesarean birth 

At any point there can be further conversations with the midwife or doctor to review the decision (NICE, 2021). A membrane sweep might be suggested before an induction of labour.

Deciding about induction is an important step, because of the implications for the labour and birth. Induction is very unlikely to lead to the baby being born the same day. While for some it works quickly, for others it will take several days.  

How does the midwife know if labour is ready to start? 

To check if the cervix is getting ready for labour, the midwife can check the Bishop score at an antenatal appointment. This involves a vaginal examination where the position and softness of the cervix is assessed. A score of 8 or more out of fifteen means labour is likely to start shortly, with or without assistance (NICE, 2021).  

Asking for the Bishop score first can help with the decision about having a membrane sweep or not.

What is a membrane sweep?  

A membrane sweep is an intervention which may be offered by the midwife or requested by the woman or pregnant person towards the end of pregnancy. This is in the hope of avoiding a medical induction.  

Membrane sweeps can be done at the usual antenatal appointment with the midwife. They are usually offered after 39 weeks (NHS, 2023).

What happens in a membrane sweep? 

If the pregnant woman or person consents to a sweep, the midwife puts one or two fingers into the vagina. They use a circling motion to ‘sweep’ the cervix open.  

This helps to loosen the membranes which loosen the protective bag of amniotic fluid from the cervix. This may encourage labour to start by releasing hormones called prostaglandins (Finucane et al, 2020; NHS, 2023).

Does a membrane sweep help bring on labour?

A membrane sweep might make it more likely that labour will start, reducing the need for induction. However, the evidence is not strong (Finucane et al, 2020; Wickham, 2020):

• Without membrane sweeping about 6 in 10 will go into labour 
• With membrane sweeping just over 7 in 10 will go into labour 

It is considered a safe method for both the mother or birthing parent and baby (Avdiyovski et al, 2019).

Does it make a difference to the birth?

There is no certainty that one or more sweeps will lead to labour starting (Finucane et al, 2020):

• It isn’t certain that a membrane sweep will prevent a medical induction 
• It doesn’t reduce likelihood of forceps or ventouse being used, or caesarean birth  
• There are no protective effects on the health of birthing mother or parent and baby 

Are there any drawbacks of a membrane sweep?

Most women and birthing people found a membrane sweep uncomfortable but acceptable (Finucane et al, 2020).  

However, in some cases, sweeps caused pain and discomfort. They may also lead to cramping and vaginal bleeding (NHS, 2023). Additionally, sweeps can cause irregular or regular contractions that may or may not start labour (Madeley, 2021).

Multiple sweeps might be performed if the woman or birthing person consents. Repeated sweeps can be a physically and emotionally exhausting experience (Madeley, 2021).

There may be an increased risk of PROM (pre-labour rupture of membranes) after a membrane sweep (Avdiyovski et al, 2019).

What happens next? 

It is possible that labour starts after this step, and no further intervention is needed. If labour doesn’t start, the next step is the offer of induction.

Who decides about induction of labour?

When induction is offered, the woman or birthing person should be given all the information relevant to their situation. This includes the fact that regular vaginal examinations and cardiotocography (CTG) are part of the induction package.  

They should have time to ask questions and consider the decision carefully with the father, non-birthing parent or birth partner (NICE, 2021). It is important that they feel comfortable that the decision they make about accepting or declining induction is right for them.  

If accepted, a planned induction date will be offered, though this might change if the maternity unit is busy. The woman or birthing person can also change their mind at any time.

How does induction of labour happen?

If the Bishop score is 6 or less, the induction method is selected from (NHS, 2023; NICE, 2021):

• hormones contained in a gel, tablet, or tampon inserted into the vagina. They may also be swallowed as a tablet 
• a balloon, sponge, or rod which expands and stretches the cervix  

Which option is right for me? 

The option used will depend on local practice and individual circumstances and preferences. This includes any previous birth history. If one method doesn’t work, the other may be tried. Either will probably take several hours.  

Depending on the NHS Trust or Board practice, with some methods it is possible to go home (Brown & Furber, 2015). In some cases that won’t be possible, and that should be clearly explained (NHS, 2023).

Are there any drawbacks of induction of labour?

The risks include:  

• hyperstimulation of the uterus, which means it contracts very quickly and can affect the baby. This might happen in 11 in 100 labours, and affect the baby's heartrate in about 5 in 100 (Heuser et al, 2013). It is more likely with the hormone methods (NICE, 2021). 
• uterine rupture, where the uterus tears and the baby must be born immediately (1 in 4000 births (UKOSS, 2023)). This is more likely during a vaginal birth following a caesarean birth.

Hyperstimulation and uterine rupture are less likely with the balloon method, which makes it a better option after a previous caesarean birth (Weeks et al, 2022).

How is induction monitored? 

The woman or birthing person tells the midwife how they are feeling, and the midwife should be looking at the pregnant person's appearance for signs that they are coping.

If the woman or birthing person agrees, the mother and baby may be monitored with cardiotocography (CTG) (NICE, 2021). This is a device strapped to the belly which records the baby’s heartbeat and the contractions. It may be attached to a recording machine or be wireless. Women and birthing people find that it can restrict their movement, which can be uncomfortable.

Vaginal examinations assess the progress of the cervix opening or dilating. These are optional and depend on the pregnant woman or person’s consent.

How can a birth partner help?

When there is a birth partner, they  can support by focusing on the pregnant woman or person, and helping them be mobile if they wish.

If in hospital, the birth partner, father or non-birthing parent can stay during visiting hours. Outside visiting hours they cannot be present until labour is confirmed by the midwife.

What happens next? 

It is possible that labour begins well after this step, and no further intervention is needed.

If it does start, contractions may not be effective, and the midwife may suggest breaking the waters.

If labour does not start after a few hours the options are to stop altogether, or rest and reassess. This could include going home for a while. After that assessment, the decision might be made (NICE, 2021):  

• to try induction again 
• to move to caesarean birth  

What is ‘breaking the waters’?

If the Bishop score is more than 6, then it’s possible to skip the previous stage and go straight to breaking the waters (NICE, 2021). Breaking the waters is also known as artificial rupture of membranes (ARM) or amniotomy (am-nee-ot-o-mee).  

If the woman or pregnant person agrees, the midwife tears the membranes using a long-handled hook passed through the vagina. The idea is that this will encourage contractions to strengthen.

This is only offered in hospital and it won’t be possible to go home after this until the baby is born. CTG monitoring will start now if it wasn’t already in place, to check how the baby responds to the waters being broken.

Are there risks of breaking the waters?

Before breaking the waters the midwife will check that the baby is lying low down in the pelvis. This is because there is a chance of the umbilical cord moving into the vagina before the baby’s head. 

This is risky for the baby so if it happens birth will be managed quickly by health professionals. Depending on how dilated the cervix is, the birth will be vaginally, possibly with forceps or ventouse, or by caesarean (RCOG, 2015).

As the idea is to strengthen the contractions, both mother or birthing person and baby will feel them more strongly.

When the membranes are ruptured there is an increased chance of infection (Wickham, 2020).

What happens next?

After the waters have been broken the options are to wait to see how labour progresses or try a synthetic oxytocin drip into the back of the hand (NICE, 2021).  

If labour does get established after this step then no further intervention is needed. Depending on how well the pregnant woman or person, and baby is doing, the CTG could be removed.  

In that case the midwife will use intermittent monitoring, using the same device used at antenatal appointments.

What does a synthetic oxytocin drip do?

Oxytocin is made in the brain and is the hormone that makes the uterus contract. The medical term is augmentation (org-men-tay-shun). Health professionals may suggest using a synthetic oxytocin drip after breaking the waters. It is also offered after a labour that started spontaneously but is not getting stronger.  

What are the drawbacks of an oxytocin drip?

Risks include hyperstimulation of the uterus and increased pain. Hyperstimulation can lead to uterine rupture, which will mean an immediate caesarean birth (NICE, 2021). The increased pain means that an epidural is commonly used. 

The baby may not react well to the stronger contractions. CTG monitoring helps keep an eye on how they are coping.

The oxytocin used in the drip does not cross back into the mother or birthing parent’s brain.  The naturally generated oxytocin may reduce as a result. This can affect the hormonal progress of labour and is linked with poorer postnatal mental health (Rashidi et al, 2022).

Women describe augmentation as leading to a negative experience of birth (Alòs-Pereñíguez et al, 2023). This can be because of increased pain and feeling less mobile because of the CTG, oxytocin drip, and possibly epidural. The father, co-parent or birth partner can help the labouring woman or birthing person to change position. They can also offer refreshments and emotional support.

In what circumstances is induction offered?

Rupture of membranes or ‘waters breaking’ 

• Before 34 weeks induction will not be offered unless there are other medical reasons. The aim will be to wait until 37 weeks before the baby is born (NICE, 2021).  
• If waters break between 34 and 37 weeks and there are no contractions, induction or expectant management will be offered unless there are other medical concerns (NICE, 2021). 
• If the waters break before 37 weeks, this is pre-term pre-labour rupture of membranes, or PPROM. It can happen in up to 3 in 100 women or pregnant people (RCOG, 2019).  
• Induction of labour will be offered if the pregnancy has reached 37 weeks and the waters break more than 24 hours before contractions start. This is called a pre-labour rupture of membranes or PROM. Induction is offered because there is an increased chance of infection after 24 hours (NICE, 2021).  

The woman or pregnant person can accept or decline any offer of induction. Healthcare professionals will explain their recommendation but must respect the decision (NICE, 2021).

Longer pregnancy or ‘going overdue’

From 38 weeks of pregnancy the midwife will start explaining what happens in a longer pregnancy (NICE, 2021a). Induction is offered to reduce the chance of stillbirth or neonatal death, which increases after 41 weeks (NICE, 2021). To understand more about this, read our article on stillbirth.

Sometimes the 41-week guide is brought forward to 39 weeks for women and birthing people over 40, but this is not in the national guidance.

Other reasons induction might be offered: 

There will be a discussion about whether induction is appropriate when the mother or birthing parent has (NHS, 2023):

• high blood pressure 
• diabetes 
• intraphepatic cholestasis of pregnancy (ICP) 

If the baby has died there should be a discussion about birth options. You can find out more about this in our article on stillbirth.

Induction is not routinely offered for (NICE, 2021): 

• a previous caesarean birth
• breech position
• the baby is small and known to be unwell (caesarean birth will be recommended) 
• a suspected larger baby with no other medical conditions (see shoulder dystocia) 
• if there has previously been a fast labour 

There is no national guidance to suggest induction should be offered to women over 40, but some obstetricians often do this (RCOG, 2013). The woman or pregnant person can decide to accept or decline the offer based on their own situation.

What is shoulder dystocia?

Shoulder dystocia (diss-TOH-shee-uh) is when the baby’s shoulder is temporarily caught in the pelvis during the birth. It happens in between 6 and 7 in 1000 births (RCOG, 2012). If not quickly resolved, it can lead to health problems for the baby. All midwives train regularly in dealing with shoulder dystocia.

Induction is sometimes offered if the baby is estimated to be over 4.5kg, because there is a concern about shoulder dystocia (RCOG, 2012).  

However (RCOG, 2012):  

• it is hard to measure the size of the baby 
• most babies over 4.5kg do not experience shoulder dystocia 
• almost half of the babies who do experience shoulder dystocia are under 4.0kg 

So the Royal College of Obstetricians and Gynaecologists (RCOG) say this shouldn’t be used as a reason for induction (RCOG, 2012).

Can I request induction?

Health professionals should consider a request for induction from the woman or pregnant person (NICE, 2021).

What are the benefits and drawbacks of induction?

Benefits

Induction may reduce the risks of a pregnancy beyond 41 weeks, including stillbirth and admission to neonatal care (NICE, 2021).  For more information, read our article on stillbirth.

Drawbacks

• Induction is associated with more vaginal examinations (NICE, 2021). The woman or pregnant person can talk to the healthcare professional in advance about their concerns, or write them down if it is easier. They can ask for someone to be with them, and can ask for the examination to stop at any time (RCOG, 2019).  
• Induction restricts place of birth to hospital (NICE, 2021) 
• The option to use a birth pool is less likely in an induced labour (NICE, 2021) 
• A higher level of pain can be expected with induced labour. Pain relief is available in hospital (NICE, 2021). 
• There is a greater chance of birth complications including hyperstimulation of the uterus, birth with forceps or ventouse, and unplanned caesarean birth (NICE, 2021; Dahlen et al, 2021).  
• A birth with forceps or ventouse is associated with a higher chance of perineal tears (NICE, 2021)
• An induced labour can last several days and require longer recovery, so the hospital stay is likely to be longer (NICE, 2021) 
• Synthetic oxytocin used to augment labour can have a negative effect on breastfeeding and postnatal mental health (Cadwell & Brimdyr, 2017; Rashidi et al, 2022) 
• There is a higher chance of the baby needing hospital care for infections up to the age of 16 (Dahlen et al; NICE, 2021) 
• Induction is associated with a more negative experience than spontaneous onset of labour (Adler et al, 2020)