Labour pain relief: opioids – pethidine and diamorphine

Some opioids, like heroin, are well-known illegal drugs but other opioids like pethidine and diamorphine are useful for labour pain, here we explain all.

What are opioids?

Opioid drugs are painkillers that are usually used in early labour (Lowth, 2017)

The most common type of opioids used during labour are pethidine or diamorphine, although some hospitals use other types (Lowth, 2017; OAA, 2019). Hospitals generally offer one of these types of opioid, but you can ask if you’d prefer a different one.

What do opioids like pethidine do during labour?

They aim to alter your mood during labour so you’re more relaxed and can rest or sleep (Lowth, 2017).

How are opioids like pethidine used?

A midwife would usually inject pethidine or diamorphine into your thigh muscle (intramuscular) during labour. 

How long does pain relief from opioids like pethidine last?

These opioids take 20 to 30 minutes to work, and each injection lasts for two to four hours (Lowth, 2017; OAA, 2019).

Are opioids good for labour pain relief?

About one in four women use opiates during labour for pain relief (Lowth, 2017). But while they’re commonly used, opioids are less effective than Entonox, and their long-term effects are unknown (Sprawson, 2017; OAA, 2019). The advantage of opioids is that they’re well known, easily available for midwives and cheap (Sprawson, 2017).

There is some evidence that opioids will give you relief from pain but they might also make you more drowsy, nauseous and sick (Smith et al, 2018). Nobody knows whether pethidine or diamorphine is better for pain relief, or which one women in labour are more satisfied with (Smith et al, 2018).

Are opioids suitable for everyone?

Some women already know that they react poorly to opioids and so would avoid them.

What are women’s experiences of pethidine or diamorphine?

Each woman responds in different way to opiates for labour pain. It’s good to remember that labour pain is different from the pain of illness or trauma (Sprawson, 2017). Some women find opioids help them feel more relaxed and less worried about the pain (OAA, 2019). Others find it disappointing as a pain reliever and feel less in control (Lowth, 2017; OAA, 2019).

What are the side effects of opioids like pethidine?

Side effects you might get include feeling woozy, sick or forgetful (NHS, 2017).  You might need oxygen if your breathing is affected (OAA, 2019). Opioids can also make you too drowsy to push effectively (Lowth, 2017).

Opioids cross the placenta and can affect your baby’s breathing. This can mean they have to go to the neonatal unit for help with breathing (NHS, 2017; Moe-Byrne et al, 2018). An opioid antidote called Naxolone can be administered to you and your baby if necessary (Lowth, 2017). But there are concerns about long-term developmental problems for the baby in these cases (Moe-Byrne et al, 2018).

Opioids can also make babies sleepy after birth, which can affect their normal instinctive behaviours (Lowth, 2017).   

How do opioids affect labour?

There is no suggestion that injections of opioids lead to further intervention in labour. They might though delay the stomach from emptying, which may be a problem if you later need a general anaesthetic (OAA, 2019).

How do opioids during labour affect breastfeeding?

The effects of opioids on babies’ normal instinctive behaviour affects breastfeeding. There’s also the risk that if you and your baby are separated because your baby goes to the neonatal unit, that interrupts bonding and hence affects breastfeeding (Moe-Lowth, 2017; NHS, 2017; Byrne et al, 2018).

Does having opioids during labour have any long-term effects?

There are no reported long-term effects.

What happens if I don’t like opioids?

If you decide you want to use an opioid, you can ask for the lowest possible dose to see how you react to it.  You can always have more but it takes two to four hours to wear off if you don’t like it.

Can midwives prescribe opioids such as pethidine?

As midwives can administer opioids, they are widely available. Yet midwives who are caring for women in non-hospital environments, like at a home birth, might be cautious about using opioids because of their impact on babies.

When do women have pethidine during labour?

Opioids should not be given too close to the birth because of the effect on the baby, though it’s difficult to know when that will be (Lowth, 2017)

What can my birth partner do to help?

The birth partner can help the woman remain in a good position, comfortable, hydrated and emotionally supported.

Can I have pethidine (or other opioids) during a water birth?

If you’ve had opioids, you’ll be discouraged from using a birth pool until the drugs have worn off. You can use Entonox and TENS alongside opioids.

Would I need any additional procedures?

You’d be offered anti-sickness medicine at the same time as the opioid injection (Lowth, 2017).

This page was last reviewed in August 2019.

Further information

Our support line offers practical and emotional support with feeding your baby and general enquiries for parents, members and volunteers: 0300 330 0700.

We also offer antenatal courses which are a great way to find out more about pregnancy and life with a new baby.

Research from the Royal College of Obstetricians and Gynaecologists (RCOG) about the use of water as pain relief in labour.

Lowth M. (2017) Pain relief in labour. Available at: [Accessed 19th July 2019]

Moe‐Byrne T, Brown  JVE, McGuire W. (2018) Naloxone for opioid‐exposed newborn infants. Cochrane Database of Systematic Reviews. (10): CD003483. Available at:…

NHS. (2017) Pain relief in labour, Available at: [Accessed 19th July 2019]

OAA. (2019) FAQs Pain Relief. Available at: [Accessed 5th August 2019]

Smith  LA, Burns  E, Cuthbert  A. (2018) Parenteral opioids for maternal pain management in labour. Cochrane Database of Systematic Reviews. (6): CD007396. Available at:…;

Sprawson E (2017) Pain in labour and the intrapartum use of intramuscular opioids—how effective are they? British Journal of Midwifery. 25(7):418-424. Available at:

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Labour pain relief: opioids – pethidine and diamorphine

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