PAIN RELIEF IN LABOUR

by Dr David Shepherd Consultant Anaesthetist, Jessop Hospital for Women, Sheffield

This page will give you information about pain that you may experience during labour and childbirth and the various methods on offer to help reduce it.

For most women childbirth happens twice in their life. For many of you reading this it will be your first baby. We hope the information we present here will act as an introduction so that you are better prepared to obtain further help and advice from the health professionals looking after you. We hope that with a better understanding and appropriate therapy the birth of your baby will be a comfortable and rewarding experience.

What causes pain in labour?

Labour begins when your uterus (womb) begins to contract. In the days before labour starts, you may experience tightening of the uterus which cause discomfort rather than pain.

Labour is said to start when you get regular contractions. Contractions increase in frequency and intensity throughout labour and can become painful in a similar way as you may experience pain in other muscles in your body when you do vigorous exercise.

At the same time the opening into the uterus (the cervix) is stretching to eventually allow your baby to pass through into your birth canal.

When the opening to the cervix is fully open (dilated) you begin what is known as the second stage of labour, when your baby is born. The baby passes through your birth canal and is born by a combination of the continuing contractions of your uterus and your conscious effort to push your baby out by using the muscles of your lower abdomen.

During your pregnancy changes happen in your body to prepare for these events. The ligaments of your pelvis loosen to permit your pelvis to relax and allow your baby to come out. Other changes occur to adapt your body to accommodate childbirth. Unfortunately, despite these changes it is likely you will feel pain. First labours are probably more painful than subsequent ones.

Sometimes when it is necessary to start off labour, or stimulate it if progress is slow, your labour may be more painful. Every person's appreciation of pain is different, and what one person can accept another may find extremely painful.

Coping in labour

You can do a lot to help. Preparing for childbirth during your pregnancy can improve these natural changes. At parentcraft classes you will be advised on exercises to make you fitter. Relaxation and breathing exercises to help you manage your labour pains. Sometimes this is all that you may need. Care with your diet, and stopping smoking are other ways you can help yourself by improving your fitness and training your body for the task that lies ahead.

Gentle exercise, breathing, posture and relaxation techniques help in early labour. A warm bath may also help. Transcutaneous Electrical Nerve Stimulation (TENS) may be of help in early labour.

A midwife will spend most time with you in labour. In their training midwives receive instruction in the methods of pain relief available. They are licensed to administer some forms of pain relief and are able to advise and seek assistance to administer other methods. Midwives are involved in giving advice at ante-natal classes.

Physiotherapists may also be involved and give advice on TENS.

Obstetricians are doctors specialising in the medicine of childbirth. As part of this they may have knowledge and administer some forms of pain relief including some local anaesthetic techniques involved in childbirth.

Anaesthetists are specialist doctors having knowledge and experience in providing all types of pain relief and can apply more sophisticated forms of pain relief to you in labour, as well as giving anaesthetics should they be necessary.

TENS

TENS has been used for pain relief in labour and is said to be effective particularly in early labour.

Treatment with TENS consists of attaching pads to your back. A low voltage electric current is passed across these pads and this stimulates your body to produce it's own natural pain relieving substances. It takes about 30 minutes before an effect is felt. The pain relief achieved is usually assessed as moderate, and is sometimes inconsistent. There are no known ill effects from TENS. For some women it is of considerable value. As labour progresses the intensity of the electrical stimulation can be increased to cope with the increased pain of contractions, but frequently stronger pain relief may be required.

TENS machines may be hired either from the hospital, or from groups such as National Childbirth Trust.

GAS (ENTONOX)

Pain relieving gas is often used to relieve labour pain. Entonox is a mixture of oxygen and nitrous oxide (laughing gas). It is designed to provide as good a pain relief as possible without causing undue sleepiness. The gas works quickly, but takes about 30-45 seconds to have an effect. To gain maximum benefit you need to start breathing it as soon as you feel a contraction start. This means the maximum action is being achieved at the height of the contraction. Entonox can be used throughout both early labour and the delivery of your baby. Entonox crosses the placenta but is not known to have any effect on your baby. The higher concentration of oxygen may help your baby. Some mothers feel light-headed during use. Occasionally nausea can be experienced, as can tiredness. Some mothers complain of a dry mouth, so you may wish to have a glass of water to sip, or small ice cubes to suck. You may experience a tingling in your fingers. This is due to overbreathing. Your midwife will know when you are doing this and remind you of your breathing exercises (sigh out slowly) and this will automatically lead to rhythmic breathing.

Entonox only works when you breath it in, so it's effects wear off very quickly once you stop breathing it, normally within a minute.

Gas mixtures will give help to relieve pain but will not remove it completely. The best use is to cope with a short periods of pain, such as the time immediately before giving birth.

Pain killing injections

The three painkilling drugs available at the Jessop Hospital are Diamorphine, Pethidine and Meptazinol. They are used on your request to relieve pain during labour. They are administered with an injection into the muscle of the thigh or buttock. The drugs can sometimes be given into the bloodstream directly for a faster effect.

There are some devices which can be programmed to allow you to administer the drug yourself (Patient Controlled Analgesia-PCA). These are commonly used for postoperative pain, but are occasionally suitable for pain relief in labour. Pressing a button releases a controlled amount of drug into the blood. Doses can be added until you are comfortable.

These drugs are available to all expectant mothers on request, but individual circumstances are taken into account. The dose given broadly depends upon body weight. You may have more than one dose during labour. Monitoring of the baby's heart rate is done at the midwives discretion (if there are no other reasons to monitor it). Side effects of these drugs are drowsiness, nausea and vomiting. They can slow your breathing down if you have too much. If given close to the birth of your baby they can slow down the baby's breathing and make him or her sleepy.

These drugs can be of great benefit to you when used within the safe guidelines. Our local guidelines allow us to give you:
Diamorphine: in early labour because it has a longer length of action.

Pethidine: in both early labour and a little later on, as it's action is shorter and less likely to affect the baby.

Meptazinol: up to late in the first stage of labour because of it's minimal effects on the baby.

Powerful painkilling drugs give good relief of pain. The effect of each injection is around two to three hours. If given often, in big doses, or too close to the delivery of the baby they can make you and your baby sleepy and may delay successful breastfeeding.

Epidural analgesia

The nerves from the uterus (womb) and birth canal go to the brain through part of your lower back (see the diagram). It is possible to bathe these nerves with local anaesthetic using an injection.

A fine tube is placed in the region of the nerves so that painkiller can be injected. This can be repeated or 'topped up' when needed during your labour. Positioning of this tube is done by an anaesthetist. Once the tube is in position you will be almost unaware of it's presence. For the second stage of labour the 'top up' is usually injected with you sitting up. This stops the pain from the lower nerves. This top up will also allow a doctor or midwife to deliver your baby painlessly if assistance is required. Any stitching can be done while the epidural is still working. An epidural will leave you pain free, but you may still have some sensation of pressure, particularly as your baby is born.

A standard epidural

This technique uses a strong local anaesthetic solution. You may find your legs may feel quite heavy with this technique.

A mobile epidural

A fine needle is placed in the region of the nerves and a single injection of painkiller is made. The fine tube is then placed in the same region so that 'top ups' can be injected. The 'top ups' are a combination of two types of painkiller. The local anaesthetic is weaker than a standard epidural and it is less likely that your legs will feel heavy. Good pain relief is achieved by the use of a second pain killer in the mixture used for 'top-ups'.

When?

This type of analgesia can be started at any time during labour. For the greatest benefit it needs to be done early enough to be useful. The normal dosage of the painkillers used will not make the baby sleepy or slow to breathe at birth as some of the other strong pain relief injections used in labour may do.

Which?

Certain factors play a part in the anaesthetist's decision process. The pain relief used before asking for an epidural is important. Mobile epidurals cannot be given within 3 hours of Diamorphine or Pethidine injections. If you have a preference please feel free to discuss it with the anaesthetist or midwife.

Advantages and disadvantages of epidurals

An epidural gives much more complete relief from discomfort in labour than any current alternative.

Normally epidural analgesia is straightforward and very effective, with little risk of harmful effects.

Epidurals may cause low blood pressure and a drip is routinely set up before they are commenced.

These methods may not always work in a satisfactory way. In this case it may be possible to switch from the mobile epidural dose to a standard epidural, but it may be necessary to reposition the epidural.

Recent research has demonstrated that you are no more likely to get backache after having an epidural for labour than if you have your baby without an epidural.

Very rarely a slow leak of spinal fluid can occur afterwards and may cause a headache, meaning you have to lie flat for a day or so until the leak seals itself. Very occasionally a second injection has to be used to seal the leak.

Despite the few disadvantages most women find that an epidural makes their labour much more enjoyable.

In the Jessop Hospital for Women this is the choice of around 35% of mothers.

Emergency caesarean section

It may sometimes be possible (depending upon assessment at the time) for a working epidural to be used for emergency Caesarean section. However a general anaesthetic may be necessary.

Assisted delivery - Forceps or ventouse

A functioning epidural can be used to make an assisted delivery a pain free experience should it be necessary.

How to obtain the pain relief you want

Advice on the various techniques, with their pros and cons, can be obtained from your midwife.

If you have a preference you can ask for whichever of the methods of pain relief you think will suit you best.

If you have any health problems please mention this to your midwife or doctor early in your pregnancy.

Occasionally there may be medical reasons why one of the methods is not suitable for you. If this is the case the reason, and the alternatives that are available will be explained to you. If you suffer from any medical condition please mention it to the antenatal clinic staff. They can then decide whether it is necessary for you to be seen by an anaesthetist before you are in labour.