Pethidine in labour: side effects, how long it lasts, pros and cons

pethidine in labour
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Pethidine is a painkiller that's often offered to mothers during labour.

Lasting for around 4 hours, it can be prescribed by a midwife as pain relief in labour.  Like any medicine, it has advantages and disadvantages. To find out more about pethidine in labour, we talked to Consultant Obstetric Anaesthetist, Dr Simon Jones. He told us, "Pethidine is a strong, opiate painkiller that can make you feel sedated (sleepy) and sometimes a bit sick, so it's important to fully understand the side effects".

What is pethidine?

Pethidine is from the opiate family of painkiller medications and is given as a muscular injection. Like other opiates, including morphine and codeine, it works by blocking pain receptors in your brain. Pethidine is only legal for use in the UK with a prescription from a doctor or midwife.

Pethidine is most commonly given to British women having a hospital birth, with studies suggesting around 25% of labouring UK mums accept Pethidine as pain relief.

Often used before having an epidural (pain medication that numbs your body from the waist down), it can be used with other painkilling medications, like gas and air (Entonox).

What are the side effects of pethidine in labour?

Common side effects of pethidine in labour include:

  • Nausea
  • Vomiting
  • Dizziness
  • Sleepiness (sedation)

Common side effects of pethidine after labour:

  • Itchiness
  • Difficulties urinating
  • Constipation
  • Shallow breathing (respiratory depression)

Source: Pethidine Patient Information Leaflet

In rare cases, studies show pethidine can cause seizures, which is why it is not recommended for women with epilepsy.

Sedation and efficacy of pethidine

A 2020 review of various painkillers used in labour found that pethidine is more likely to make you feel sedated (drowsy or sleepy) than other painkillers. Many women find that pethidine can make them feel less in control of their labour because of this sedation.

Some studies have found that pethidine only has a modest pain-relieving effect.

Real mum's experiences of pethidine

Sheree, mum of one told us

"Pethidine didn't really control my pain as much as I was hoping. However, it did make me really sleepy, all I wanted to do was go to sleep. I didn't really feel present at my own labour, so I don't think I would use it again."

Davina, who has four children, really liked pethidine during her first labour and found it helped her relax.

"I had a small dose of pethidine which really helped me relax and brought down my blood pressure. The idea of giving birth had worried me for months before. Pethidine was really helpful because the sedative effect was just what I needed to relax into labour".

How does pethidine in labour affect the baby?

As pethidine is an opiate drug, it can cross into the placenta through the umbilical cord and therefore affect your baby. If you use pethidine in labour, it's important not to use your placenta for placenta encapsulation.

Pethidine use in labour can cause:

  • Your baby's breathing (respiratory depression) to be affected
  • A less alert baby at birth (likely more sleepy)
  • Baby to be less interested in feeding for the first few hours

Source: Lactmed Database, 2021

It's best to use pethidine in the early stages of labour. This will reduce the likelihood of any side effects in your baby. You might worry about taking pethidine because of the potential effects on your baby. However, your healthcare team will know when it's right to use pethidine and when it's not advisable. Remember that your obstetric team have lots of experience in using pethidine for pain relief in labour.

Obstetric Anaesthetist Dr Stephen Jones explains, "Pethidine can build up in the baby's blood and that's why I would only recommend having one or two doses. Usually, there's no problem with giving pethidine early in labour. We will need to monitor baby after birth if you have pethidine just before you deliver".

What happens if my baby is affected by pethidine?

Most babies born after pethidine is used in labour are unaffected. Worries about your baby are natural, but it's rare for pethidine to cause major issues.

If your baby needs assistance to breathe, this will mean some time in the neonatal unit. As pethidine is short-acting, it really won't be long until your baby is completely normal again, back in your arms.

Doctors can give your baby medication (naloxone) to reverse the effects of pethidine. However, the evidence for naloxone used in this way is low-quality, according to this review from 2018.

Paediatricians will be on hand right away if needed. They will make sure your baby is looked after and know exactly what to do.

How long does pethidine last?

Pethidine works quickly, usually within about 10 minutes. It will last for 2-4 hours (Source: UK Medicines Compendium).

If you have a long labour, you can be given pethidine again once it has worn off.

Is pethidine in labour suitable for everyone?

Pethidine may not be suitable for you. It's important to talk to your midwife and/or consultant about pain relief while you're writing your birth plan.

You should not take Pethidine if you have a diagnosis of:

  • Some liver or kidney issues
  • Epilepsy
  • Asthma, sleep apnoea or Chronic Obstructive Pulmonary Disorder (COPD)
  • Low blood pressure (hypotension)
  • Myasthenia gravis (which causes muscle weakness)

Source: Pethidine, British National Formulary, National Institute of Clinical Excellence (NICE)

When to discuss pethidine in labour with your health team

You must discuss pethidine with your healthcare team if you have any other illnesses. Especially if these conditions affect your muscles, breathing or neurological abilities.

If you are taking other medications, you will need to know if there are any worrying drug interactions. Interactions happen when drug side effects combine in a way that can make you unwell. If you have certain long-term, chronic illnesses, your healthcare team will help you understand which pain medications are a good choice.

Pethidine: the pros and cons

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Pros of PethidineCons of Pethidine
✅ Fast-acting: within 10 minutes for some labouring mothers ✅ Lasts 2-4 hours ✅ Easy to top up if you have a long labour ✅ Can make you feel or be sick ✅ Many labouring women find it very effective ✅ Can lower your blood pressure ✅ May help you relax if you are anxious ✅ Can be used at any birthing location (home, midwife-led unit, hospital) ❌ A few mums don't like how it makes them sleepy in labour ❌ Some women don’t find it effective ❌ Can make you feel or be sick ❌ Cannot be in water while under the effects of pethidine, so it might affect your planned water birth ❌ It may make you feel dizzy ❌ It can affect the baby’s breathing and feeding, if given later in labour ❌ Pethidine might make you feel less in control of yourself and your birth, compared with other painkillers used in labour

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Tannice Hemming
Maternity and family writer

Tannice Hemming has worked alongside her local NHS in Kent and Medway since she became a parent and is now a mum of three. As a Maternity Voices Partnership Chair, she bridged the gap between service users (birthing women and people, plus their families) and clinicians, to co-produce improvements in Maternity care. She has also worked as a breastfeeding peer supporter. After founding the Keep Kent Breastfeeding campaign, she regularly appears on KMTV, giving her views and advice on subjects as varied as vaccinations, infant feeding and current affairs affecting families. Two of her proudest achievements include Co-authoring Health Education England’s E-learning on Trauma Informed Care and the Kent and Medway Bump, Birth and Beyond maternity website.