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Medical Pain relief in labour
- thesmartdoula
- 2 days ago
- 6 min read
Pain relief in labour
Before you start reading this blog, I would recommend you hop over to my other blog about non-medical pain relief in labour.
Not because I want to discourage you from using medical pain relief in labour, but all of the things in the first blog can be used alongside medication - layering up is a great strategy for labour and one you need to get in on!
Paracetamol for pain relief in labour
What is Paracetamol
You most likely already know about this one! Paracetamol is a common painkiller that many people have been told is safe in pregnancy.
What the evidence says
There is minimal research showing that paracetamol helps with pain in labour. Many studies that demonstrate its effectiveness are based on IV paracetamol infusions.
Some theories suggest it might slow early labour because it limits prostaglandin production, but this is not proven.
Prostaglandins are what help your cervix soften, although paracetamol does inhibit prostaglandins, its target is in the brain, and there is no current evidence that it weakens the prostaglandins in the cervical tissue - it is certainly worth a pause, though.
Paracetamol does not require a prescription; it's freely available at home.
Common advice in early labour is to pop a paracetamol and have a bath, and it is often given out in maternity units.
Paracetamol may be effective for the aches and pains of early labour, but so is heat, water and a TENs machine!
Nitrous Oxide
I have a whole blog on this one here:
Opioid Analgesics: Codeine, Dihydrocodine, Pethidine, Diamorphine and Remifentanil
These drugs are opioids. They can dull pain but have side effects and cross the placenta to your baby.
Opioids also pass through your breastmilk to your baby after birth, and for this reason and the fact that they pass the placenta, they aren't usually given close to birth (though you can't always tell!)
You can find out more about opioids and breastfeeding here: https://www.breastfeedingnetwork.org.uk/factsheet/analgesics/
An opioid is a class of drugs that includes natural substances derived from the opium poppy plant, as well as semi-synthetic and synthetic compounds created in laboratories.
Codeine and Dihydrocodine
Codeine itself is not recommended in breastfeeding women, as it passes through the placenta and also passes through breastmilk.
In 2013 the authorities issued advice on the use of codeine in pregnancy following the death of a breastfed infant in 2005 due to morphine toxicity following maternal use of codeine. It was advised that codeine is contraindicated in women who are breastfeeding owing to the increased risks to the infant.
For this reason, codeine isnt commonly prescribed during birth.
Dihydrocodine, however, is metabolised differently and is safer for breastfed infants, though it still may have some effects, and babies should be watched carefully after birth.
There isnt a lot of recent evidence on dihydrocodeine in labour, and hardly any with it in itsform it is given today -orally.
One older study into pethidine vs dihydrocodeine showed 'When the total number of doses for each drug were compared, pethidine 100 mg gave “good” pain relief in 64.2% against 41.4% when dihydrocodeine 30 mg was used'
Dihydrocodine is classed as a weak opioid and is sometimes prescribed in early labour, like paracetamol, it may be effective against aches and pains, but its dependant on the person!
Pethidine and Diamorphine
How they work:
These are injected into the muscle. They act in about 15–20 minutes.
Benefits
✔ Can reduce pain more than a placebo
One study showed women were significantly more dissatisfied with a placebo, compared with pethidine, both during labour and after labour 54% versus 25%; p=0.00004.
✔ Can improve satisfaction compared with no pain relief
✔ Dependent on the homebirth team this could be given at home (a prior prescription will be needed)
Risks
Can make you drowsy, sick or constipated. This study showed that maternal pulse significantly decreased, and maternal nausea-vomiting was frequent in the study group that received pethidine.
Can make you less alert and harder to move, which may have an impact on fetal positioning
Can cross the placenta and make your baby drowsy, which may affect breastfeeding and breathing after birth. Research shows this is most likely if the dose is administered two or three hours before birth. The higher the dose to the mother, the greater the effect on the baby (Yerby 1996).
It can affect your baby's condition at birth as assessed by the APGAR score; mothers who had no drugs in labour had a baby with an APGAR score of 7 or less at one minute 7.5% of the time. Mothers who had pethidine had a score of 7 or less at one minute 12.3% of the time (Chamberlain, 1997).
Diamorphine does pass into breastmilk and may affect your baby if it is given shortly before your birth.
This article, written by AIMS, gives more information and full study references.
Remifentanil (IV Patient-Controlled Analgesia)
How it works
Given through a pump into a vein. You press a button to give yourself doses.
Benefits
✔ Fast acting (1–2 minutes)
✔ Can provide stronger pain relief than injected opioids like pethidine and is more effective than nitrous oxide
✔ Can reduce the need for an epidural in some cases: in the RESPITE trial, which compared pethidine with remifentanil, the proportion of women requiring conversion to epidural analgesia was significantly lower with remifentanil-PCA than with pethidine.
✔ Although it crosses the placenta, it undergoes rapid metabolism in the fetus, which may make it safer for the fetus compared to other opioids
✔Associated with lower rates of cesarean sections and operative vaginal deliveries than epidural
Risk
Still an opioid with similar side effects (nausea, drowsiness)
You may need oxygen supplementation
Can cause itching
You must be monitored closely
Requires IV and an anaesthetist
Less effective than an epidural
Does not provide complete pain relief but rather modifies pain perception by attenuating nociceptive transmission through μ-opioid receptor mechanisms. This could be a positive or a negative!
It crosses the placenta. Studies have not shown a difference between this and other opioids in terms of APGAR scores
Can only be given in a hospital
This is a good review of available evidence
Sterile Water Injections
What they are
Small amounts of sterile water are injected under the skin over your lower back. This triggers the body’s pain-relieving responses.
Evidence
National guidance (NICE) recommends considering sterile water injections for back pain in labour.
They can reduce back pain from about 10 minutes up to 3 hours, although the injection may sting at first.
Some older systematic reviews found the evidence not strong enough to make firm conclusions, but more recent trials support a benefit for back pain relief and satisfaction,
Benefits
✔ Can help reduce back pain
"sterile water injections induce a statistically significant, dramatic analgesic effect on the low back pain experienced by women during labour; lasting from 10min and up to 2h post-administration … [They] have proved to be a justifiable alternative to the use of narcotics for birthing women and their midwives who are concerned about unwanted side effects for mother and baby. Their effect has been described as powerful, rapid and effective, with the potential to decrease or delay the use of epidural anaesthesia.” (Fogarty 2008: 162).
✔ Available without a prescription in any birth environment
✔ Works quickly
✔ No impact on baby’s alertness or breathing
✔ Does not affect the ability to move or push
✔ Can be used in any birth setting and with other pain relief
Risks
Painful to give with the pain lasting several minutes
Does not help with contraction pain
Research varies in quality, so the certainty of effect is lower than for an epidural.
Epidural
This one deserves its own blog - Coming soon!
Comparing Options
Research and reviews suggest a spectrum of pain relief and risk:
Paracetamol – lowest effect, lowest risk
Injected opioids (like pethidine or diamorphine) – moderate relief, more side effects
Remifentanil PCA – stronger relief for some, requires careful monitoring
Sterile water injections can help relieve back pain with minimal side effects
Epidural – best pain relief overall, but includes other risks not covered here, such as longer second stage and possible forceps/ventouse delivery.
Summary
Choosing pain relief is personal, and researching the risks and benefits is not something you want to be doing when you are in labour.
Even if your plan A is not use medical pain relief, it is a good idea to look into the options during pregnancy so that you have a good understanding of what your preferences would be should you choose additional pain relief during labour.
Knowing what the risks are for each type will enable you to plan to reduce them. For example, if your choice may leave you unable to move, how can you facilitate good fetal positioning? If your choice requires an IV, where would you want this placed?.
Do you want anti-sickness medication alongside your options?
Beginning with non-medical options, which do not carry risks to mother or baby and layering these up together before moving onto medication may feel like the best plan for some people, whilst others may feel strongly that they wish to opt for an epidural from the get-go.
Who am I?
I am Charlotte, a Virtual Doula, providing bespoke evidence-based pregnancy support to families who want an empowering birth.
With 10 years + of clinical research experience, a biomedical science degree, and two hospital births under my belt, I use my knowledge to provide pregnancy support to help you make informed decisions about your pregnancy, birth, and postpartum.
I provide pregnancy support for all types of births, including hospital births, helping you to navigate NHS guidelines and have an empowering, positive birth.
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