What is Pethidine and how does it work?
Pethidine is the most commonly used morphine derivative for pain relief and relaxation during labour. The drug is usually administered via an injection into muscle (bottom or thigh) and occasionally intravenously, often with the patient controlling the pethidine pump. The drug is both an analgesic (painkiller) and an antispasmodic, so may help you feel relaxed as well as reducing pain.

As Pethidine can often cause nausea and vomiting it is often given with an anti-emetic drug to prevent vomiting.

When can I use Pethidine?
Pethidine is usually given in the first stage when labour is clearly underway but the birth is likely to be more than three hours away. You should be examined before Pethidine is given, and if it looks like the birth is less than three hours away then you will probably be discouraged from having the drug. There's a good reason for this: Pethidine crosses the placenta to your baby and if your baby is born within a couple of hours of you having the drug then the drug may have a strong effect on the baby. At its most serious, the effect of Pethidine on your baby can necessitate assisted breathing after delivery, it also commonly causes drowsiness in a new baby and so may interfere with getting breastfeeding established.

Once administered Pethidine takes about 20 minutes to take effect and then wears off after three to four hours. In some cases of extended labour you may be given another shot of pethidine.

Advantages

  • Pethidine may help you relax and regather strength for the later stages of labour
  • Pethidine can be given by a midwife without a prescription and so doesn't require a doctor
  • Pethidine may be used for home births, although not all midwives will offer it as an option

Disadvantages

  • Individual reactions to Pethidine vary greatly, so it does not have the same pain-relieving and relaxing effects for all women. While some women will find the drug fantastic, others may find it is of limited use against the pain, or that the side-effects outweigh the benefits
  • Some women will find that Pethidine makes them very nauseous, whether or not they've had an anti-emetic
  • Some women will feel dizzy and/or drowsy under the influence of Pethidine
  • Pethidine may make you feel out of control or disoriented during labour and afterwards you may even discover that you have no memory of labour and birth at all
  • Pethidine is a powerful drug that passes through the placenta and can affect the baby to varying degrees. This is more likely if the pethidine is given within three hours of the birth. Your new baby may be drowsy and in the most serious cases may require an injection to counteract the effects of the drug and assistance with breathing at the outset
  • Although most of the drug should be out of your baby's system within 24 hours, the effects of the drug may linger for several days, leaving your baby sleepy and less responsive and so making it more difficult to establish breastfeeding

Availability
Pethidine or a similar alternative will be available in hospitals. As a midwife can administer Pethidine without a doctor's prescription, it can also be used in home deliveries. However, not all midwives are happy using Pethidine for home deliveries, so if it's a drug that you're interested in using then it's best to check in advance.