The pain of childbirth is likely to be the most severe pain that a woman experiences during her lifetime. The pain of labour and delivery varies among women, and each labour of an individual woman may be quite different.
How does pain originate in labour?
First stage of labor (0 to 10cm dilated) – Pain at this time occurs during contractions, is cramp-like in nature, originates in the uterus and cervix.
Second stage of labor (Pushing) – Pain from distention of the vagina, perineum, and pelvic floor and stretching of the pelvic ligaments is the hallmark of the second stage of labor. Second stage pain is more severe than first stage pain. In addition, a labouring woman may experience rectal pressure and an urge to “bear down” and expel the fetus as the presenting part descends into the pelvic outlet.
The adverse effects of labour pain
- Increased stress hormone levels may reduce blood flow to the uterus and baby
- Psychological effects
Drug Options for pain relief
- Opioids – Morphine, Fentanyl and Pethidine
- These can be given via intramuscular or intravenous injection depending on the drug, and occasionally be given via a PCA (or patient controlled analgesia) pump
- Opioids are generally more effective in the early stages of labour, where they may have a sedative effect. They generally do not work as well in the later stages of labour and can be associated with respiratory difficulties in the baby if given too close to delivery
- Nitrous oxide gas
- This can be self-administered during labour and has the advantages of being quickly metabolized by the mother with minimal effects on the fetus
- Local anaesthetic injection
- Pudendal blocks can be used to anaesthetize the lower vagina and bottom – this is generally useful during the second stage of labour, especially during a forceps or vacuum delivery
- Epidural / Spinal anaesthesia
- These techniques generally provide excellent pain relief. Some women may have medical conditions where these are the preferred methods of pain relief in labour, or where they cannot be used at all.
- A spinal anaesthetic provides a more dense block but cannot provide continuous pain relief as with an epidural
- There are risks associated with a more invasive pain relief option such as an epidural
It is impossible to summarise such a large topic in one page, however, every woman’s requirement for labour pain relief and options needs to be individualised. It is important to be aware of and consider all options, whether involving drugs or drug free.