Topic Overview

To help control the pain and stress of labour, you may get pain medicines. The medicine can be injected into a vein or into the muscle. The most common pain medicines used are opioids. Examples include fentanyl, morphine, and nalbuphine.

How opioids work for labour pain

Opioids suppress how you perceive pain, and they calm your emotional response to pain. They do this by reducing the number of pain signals sent by the nervous system to the brain. They also reduce the brain's reaction to those pain signals.

An opioid can help you relax between contractions and decrease the pain. But it does not take all the pain away.

Opioids make you drowsy for a short time. They can also slow your labour. But they are less likely than epidural anesthesia to cause you to have a forceps or vacuum delivery.^{footnote 1}

Side effects

The most common side effects of opioids include:

• Feeling dizzy or light-headed, or like you might faint.
• Feeling drowsy.
• Feeling sick to your stomach or vomiting.

Opioids are not used when you are close to delivery. That's because they can affect a newborn's breathing. They can also make the baby sleepy and less interested in breastfeeding if they are given close to delivery.