Given by mask or mouthpiece, takes 20-30 seconds to take effect and works for as long as it is inhaled. Nitrous oxide is very easy to use but needs to be timed carefully for maximum benefit. It also helps with relaxation. This is an excellent form of analgesia for baby in relation to breastfeeding. Nitrous oxide will not harm your baby but may make your mouth and throat become dry. You may experience a little disorientation, nausea, vomiting or claustrophobia.
Given by injection into a muscle, which takes 15-20 minutes to take effect, or into a drip, which takes 5-20 minutes to take effect. Relief of pain with injection lasts from 2-3hours. The effect of pethidine is that it takes the edge off the pain and will help with relaxation. You may experience some nausea and/or vomiting and pethidine is often given with a nausea suppressant to help prevent this occurring.
This is given in the form of an injection into the spine through a fine plastic tube and take 15-20 minutes to take effect. The local anaesthetic can be pumped slowly and continuously or "topped up" as required approximately every two hours, and should enable you to rest as needed throughout labour. There may also be much less/no pain during labour. The disadvantages are that you will be confined to bed as sensation and movement is reduced. The labour becomes more technical, requiring a drip and continuous monitoring of both you and your baby. You may also need a catheter to help you pass urine and keep your bladder empty. This also helps with the descent of the baby.