INTRODUCTION
The joy of every pregnant mother is to have a safe delivery and a healthy baby. The role of a competent midwife in achieving this cannot be overemphasized. An understanding of the concept/process of labour and management of normal labour, is therefore of utmost importance.
Labour is defined as the process by which the fetus, placenta and membranes are expelled through the birth canal, it involves more than the expulsive muscular effort of the uterus, being a strenuous ordeal in which the woman’s whole body participate.
Normal labour occurs when the fetus is born at term, and present by the vertex, the process is completed spontaneously (by the natural unaided effort of the mother) the time does not exceed 18hours, no complication arises There are four stages of labour namely: First, second, third and fourth stage of labour.
1. First stage of labour – This is the dilatation phase. It begins with regular rhythmic contraction and is complete with the full dilation of the cervix. Average duration in primigravida is 12 hours and 6 hours in multigravida. This involves
– The latent phase- This occurs from cervical dilatation of 0-3-4cm. This phase begins with mild, irregular uterine contraction that softens and shortens the cervix. Contractions are mild and short, lasing 20-40 seconds. The latent phase may last up to 6-8 hours in a primipara.
– The active phase – In this phase, the cervix undergoes rapid dilatation. It starts from cervical dilatation of 3- 4cm and is completed when the cervix is fully dilated. Contractions grow stronger lasting 40-60 seconds and occur every 3-5 minutes. Lasts 3hrs in primip and 2 hours in multip It is characterised by rapid cervical dilatation and descent of the presenting part.
– The transitional phase – This is the stage of labour when the cervix is 8cm dilated till full dilatation of the cervix. Contractions may reach the peak of intensity occurring every 3 minutes. There may be a brief lull in the intensity at this time.
2. Second stage of labour – This is the expulsive phase. It begins with the full dilation of the cervix to expulsion of the baby. Average duration is about thirty minutes in primigravida and 15 minutes in multigravida
3. Third stage of labour – This involves the separation and expulsion of placenta and its membranes. It also involves the control of bleeding. It starts from the expulsion of the baby to the expulsion of placenta and its membrane. Duration is 15 minutes
4. Fourth stage of labour – This is the period of one hour following the birth of the baby. It is described by some in order to stress the continued vigilance which is necessary because of the risk of post -partum haemorrhage.
DEFINITION OF TERMS
Pregnancy: A condition of having a developing embryo or fetus within the body, the state from conception to delivery of the fetus. The normal duration is 280 days 40weeks or 9 months.
Midwifery: Is the art and science of caring for women undergoing normal pregnancies, labour and puerperium.
Primigravida: A woman pregnant for the first time.
Multigravida: A pregnant woman who has previously had more than one pregnancy.
Grande- multigravida: A pregnant woman who has had 4 or more previous pregnancies.
Multipara: A woman who has given birth to more than one viable infant.
Gravid: means pregnancy
Gravida: a pregnant woman
FACTORS INFLUENCING THE ONSET OF LABOUR
The exact cause of spontaneous labour is not clear, however, it appears to be the result of a combination of factors which can be hormonal and mechanical.
– Hormonal
– Mechanical factors
Effect of hormones on onset of labour
OESTROGENS – They have the following effects:
1 Hypertrophy of the myometrium accomplishing the normal growth necessary for forceful contraction of labour and rise in the contractile protein level in the myometrial cells
2 Stimulation of the synthesis, release and effect of oxytocin and prostanglandins. It increases responsiveness to oxytocin by increasing expression of oxytocin receptors
3 Stimulation of the development of progesterone receptors
4 Increased irritability of the myometrium is ascribed generally to oestrogen.
2 PROGESTERONE
Progesterone produced by the placenta relaxes uterine muscles by interfering with the conduction of impulses from one cell to the next. It has an opposite effect to oestrogen, progesterone has a sedative effect on uterine muscles, so its withdrawal at the end of pregnancy may facilitate the onset of labour.
3. OXYTOCIN
Oxytocin from the posterior pituitary gland has a stimulating action on the pregnant uterus and can be used to induce labour. The number of oxytocin receptors strikingly increase in myometrium and decidua tissues near the end of term. Oxytocin acts on decidua tissue promoting the release of prostaglandin
4 PROSTANGLANDIN
They are synthesized in the decidua at term in response to the release of oestrogen by the feto placenta unit. They play a major role in the initiation of labour. Prostaglandin acts by inhibiting calcium binding, thereby increasing free calcium which in turn stimulates uterine contraction. Both oxytocin and prostaglandin act synergistically inhibiting calcium binding and stimulate uterine contraction. Its synthesis reaches its peak in third stage which helps in placental expulsion and control of post -partum haemorrhage. Its synthesis is triggered by rise in oestrogen level, mechanical stretching, stripping of membranes, altered oestrogen and progesterone balance.
Before labour, Prostaglandin stimulates cervical ripening, the breakdown of cervical connective tissue causing it to be soft, flexible and capable of dilatation.
The level of prostaglandin or their metabolites in amniotic fluid, maternal plasma and maternal urine are increased during labour. During labour, they stimulate myometrial contraction
Others are:
5 INTRA-AMNIOTIC VOLUME
Distension of the uterus may play a role. Rupture of membrane with a decrease in uterine volume is used to induce labour.
MECHANICAL– As pregnancy advances, there is an increase in the contractibility of the uterus, which b ecomes more susceptible to stimulation as term approaches. The pressure of the presenting part on the nerve endings in the cervix play some part- experience shows that labour is more likely to start on time when the head is engaged than when it is high. Over distension of the uterus as occurs with twins or polyhydramnios, tends to induce labour.
PREMONITORY SIGNS OF LABOUR
During the three weeks prior to onset of labour, certain changes take place which when manifest are useful to determine the approach of labour, they are;
1. Lightening: This is the sinking of the uterus, which take about two or three weeks before term, because the fundus no longer crowds the lungs, breathing is easier the heart and stomach can function better and the relief experienced by the woman is described as lightening. It occurs because the symphysis pubis widens, the softened, relaxed pelvic floor sags by as much as 4cm allowing the uterus to descend further into the true pelvis. The lower segment stretches and the fetus sinks further down into the uterus. The fundus is therefore at a lower level, the uterus becomes more prominent and if the abdominal muscles are in good tone as found in a primigravid woman, and no disproportion exist, the head will enter the pelvic brim and become engaged. In multiparous women the bracing action of firm abdominal muscles may be absent, and the uterus will then sag further forward, the abdomen becomes pendulous and the fetal head does not as a rule become engaged. Walking is more difficult at this time, relaxation of the pelvic joint may give rise to back ache or pain in the region of the symphysis pubis vague discomfort may be experienced in the lower abdomen, groins and thighs. Vagina secretion becomes more profuse.
2. Frequency of micturition: This may be due to pressure of the fetal head on the bladder limiting its capacity and requiring it to be emptied more often. But sometimes there is a state of mild incontinence or poor control of the urethral sphincter, which may be accounted for by the lax condition of the softened pelvic floor at this time.
3. False pains: These are erratic and irregular contractions, causing the uterus to contract and relax, whereas in true labour the uterus contracts and retracts. They may be unduly troublesome and some consider this to be mild in coordinate uterine action.
4. Taking up of the cervix; Taking up of the cervix occurs because it is being drawn up and merged into the lower uterine segment. Shortening of the cervix is usually looked for, when in the interest of mother or child, labour must be induced.
DIFFERENCES BETWEEN TRUE AND FALSE LABOUR
TRUE LABOUR
FALSE LABOUR
• Marks the onset of labour
Appear days before labour
• Associated with efficient uterine contraction
Inefficient contractions of uterus/painful spasm of uterus, bladder and abdominal wall
• Occur at regular intervals
Irregular intervals
• Increase in frequency and duration
No change
• Bloody show present
No show
• Descent of presenting part
Inefficient to push the presenting part
• Contractions start at the back and radiate to the front
Mainly in the front
• Hardening of uterus
No hardening of the uterus
• Progressive effacement
• and formation of bag of membranes
No change in cervix
• Sedation/enema does not interfere with true labour
Relieves the pain
• Dilatation of the cervical os
No change in size and shape of cervix
MECHANISM OF NORMAL LABOUR
This refers to the series of changes in position and attitude that the fetus adopts during its passage through the birth canal. As the fetus descends, soft tissues and bony structures exert pressures which lead to descent through the birth canal by a series of movement which are referred to as ‘mechanism of labour’.
Engagement – Engagement is said to have occurred when the widest part of the presenting diameter has successfully passed through the brim of the pelvis. The number of fifths of the fetalhead palpable abdominally is often used to describe whether engagement has occurred. If more than two-fifths of the fetalhead is palpable abdominally, then the head is not engaged.
Denominator – The most identifiable peripheral bony point on the presenting part. In a vertex presentation, the denominator is the occiput, while in a breech presentation, the denominator is the sacrum
Attitude – This refer to the relation of the fetal parts to one another. The normal attitude of the fetus is that of moderate flexion of the head, flexion of the arms onto the chest and flexion of the legs onto the abdomen
Lie – The fetal lie refer to the relationship of the cephalocaudal(long) axis of the fetus to the cephalocaudal(long) axis of the uterus.
Presentation – This is determined by the fetal lie and by the body part of the fetus that enter the pelvic passage first. This portion of the fetus is referred to as the presenting part. This refer to the part of the fetus which lie at the pelvic brim or in the lower pole of the uterus
Station – This refer to the relationship of the presenting part to an imaginary line drawn between the ischial spine of the maternal pelvis. The Ischia spine is being designated as zero station. A negative number is assigned to presenting part higher than the Ischia spine, while a positive number indicate that the presenting part has passed the Ischia spine.
Presenting part – The portion of the presentation overlying the internal os or felt through the cervical canal on internal examination. eg the presenting part in a cephalic presentation could be vertex, face or brow.
Position – This refer to the relationship between the denominator of the presenting part and six parts on the pelvic brim. The occiput is directly laterally to the left in left occipito-anterior (LOA)
Principles common to all mechanisms are:
• Descent takes place
• Whichever part leads and meet the resistance of the pelvic floor will rotate forward until it comes under the symphysis pubis
• Whatever emerges from the pelvis will pivot around the pubic bone.
At the onset of labour, the most common presentation is the vertex, and the most common position is either left or right occipito anterior (ROA);
The mechanism therefore is
• The lie is longitudinal
• The presentation is cephalic
• The position is right or left occipito-anterior
• The attitude is that of good flexion
• The denominator is the occiput
• The presenting part is the posterior part of the anterior parietal bone.
MAIN MOVEMENTS OF THE FETUS
DESCENT – Descent of the fetal head into the pelvis often begin before the onset of labour. Further descent takes place during the first stage of labour, and is brought about by the action of the uterine contractions. When the head meets resistance flexion is increased and the dilating cervix allows the flexed head to descend.
FLEXION – Flexion increases throughout labour, with the sub-occipito-frontal diameter of 10cm lying at the pelvic brim but when flexion is increased the sub-occipito bregmatic diameter of 9.5cm engages, this smaller diameter facilitate descent. The effect of increased flexion of the head is that the occiput becomes the leading part.
INTERNAL ROTATION OF THE HEAD –The occiput which is the leading part reaches the pelvic floor 1st and rotates 1/8th of a circle to appear under the pubic arch, the head is in an anterior posterior diameter of the pelvis. The head slips beneath the sub-pubic arch and crowning occurs. Crowning is the term used when the occipital prominence escapes under the sympysispubis and the head no longer recedes between uterine contraction
EXTENSION OF THE HEAD –Extension is a movement by which flexion of the head is undone. The nape of the neck pivot on the lower border of the symphysis pubis, while the sinciput, face and chin sweep the perineum and are born by a movement of extension.
RESTITUTION –This is a turning of the head to undo the twist in the neck, in a vertex LOA the occiput restitute 1/8th of a circle to the left, back to where it was before internal rotation took place.
INTERNAL ROTATION OF THE SHOULDERS – This is a movement similar to internal rotation of the head, the shoulders in an ‘LOA’ are in the left oblique diameter of the pelvic cavi ty. The anterior shoulder reaches the pelvic floor 1st and rotates forward 1/8th of a circle bringing the shoulders into the ante- posterior diameter of the outlet. The anterior shoulder lie under the symphysis pubis
EXTERNAL ROTATION OF THE HEAD – This is a turning of the head which accompanies internal rotation of the shoulders, the occiput turns a further 1/8th of a circle always in the same direction as in restitution
LATERAL FLEXION – The shoulders are often born sequentially. The anterior shoulder slips beneath the sub pubic arch/symphysis pubis and the posterior shoulder sweeps/passes over the perineum. The remaining part of the body is born by movement of lateral flexion towards the mother’s abdomen
PHYSIOLOGY OF FIRST STAGE OF LABOUR
• UTERINE ACTION
• MECHANICAL FACTORS
Uterine action – These are the changes that occur in the uterus during labour
1. Fundal dominance – Each of the uterine contraction starts in the fundus, near one of the cornua, and it spreads across and downwards. The area of myometrium near the cornuaact as pacemakers to coordinate the contractions. The contraction last longest in the fundus where it is also most intense and the peak is reached simultaneously over the whole uterus and the contraction fades from all parts together. This pattern allows the cervix to dilate, and the strongly contracting uterus to expel the fetus.
2. Polarity – This is used to describe the neuro-muscular harmony between the upper and lower uterine segment of the uterus throughout labour. These two poles act harmoniously during labour. The upper pole contract strongly and retracts to expel the fetus; the lower pole contract slightly and dilates to allow for expulsion. Once polarity is disorganised, the progress of labour will be inhibited.
3. Retraction – Uterine muscles have a unique property, during labour, the contraction does not pass off totally, but muscle fibres retain some of the shortening of the contraction instead of becoming completely relaxed, this is referred to as ‘retraction’. It assists in progressive expulsion of the fetus; the upper segment becomes progressively shorter and thicker and the cavity diminishes. Uterine contraction occurs in early labour every 15-20 mins and may last for about 30 secs, they are fairly weak and bearable.
4. Formation of upper and lower uterine segments – The body of the uterus divides into two segment which are anatomically distinct by the end of pregnancy. The upper uterine segment is mainly concerned with contraction and is thick and muscular. The lower uterine segment is the thinner distensible area. The lower segment develops from the isthmus and is about 8-10cm in length. When labour begins, the retracted longitudinal fibres in the upper segment pull on the lower segment causing it to stretch; this is aided by the force applied by the descending head or breech.
5. The retraction ring – Retraction ring is a ridge that forms between the upper and lower uterine segment, this is physiological in origin. The term ‘Bandl’s ring is used for an exaggerated degree of this phenomenom. It becomes visible above the symphysis pubis in obstructed labour. The normal retraction ring gradually rises as the upper uterine segment contracts and retracts and the lower uterine segment thins out to accommodate the growing fetus. Once the cervix is fully dilated and the fetus can leave the uterus, the retraction ring rises no further.
6. Cervical effacement – This may take place during the last few days of pregnancy or during labour. The muscle fibres surrounding the internal os are drawn upwards by the retracted upper segment and the cervix merges into the lower uterine segment. The cervical canal widens at the level of the internal os. In the primip, cervical dilatation does not begin until effacement is complete while in multip, the external os begin to dilate before effacement is complete.
7. Cervical dilatation – Dilatation of the cervix is the process of enlargement of the os uteri from a tightly closed aperture to an opening large enough to permit passage of the fetalhead. Cervical dilatation is measured in centimetres and full dilatation equates about 10cm. Dilatation occur as a result of uterine action, counter pressure applied by the bag of membranes and the presenting part.
8. Show – As a result of the dilatation of the cervix, the operculum which is formed by the cervical plug during pregnancy will be lost. It is a blood stained mucoid discharge seen few hours before or few hours after labour starts. The blood comes from ruptured capillaries in the parietal decidua where the chorion has become detached and from the dilating cervix.
MECHANICAL FACTORS
1. Formation of fore waters – As the lower uterine segment forms, the chorion becomes detached from it and the increased intrauterine pressure causes the loosened part of the sac of fluid to bulge downwards into the dilating internal os to the depth of 6-12mm. The well flexed head fits snugly into the cervix and cuts off the fluid from the front of the head from that which surrounds the body, the former is referred to as the fore water and the latter, the hind water. The effect of separation of the fore waters is to prevent the pressure applied to the hind water during uterine contraction from being
applied to the fore waters thus keeping the integrity of the membranes during the first stage of labour.
2. General fluid pressure – with the membranes intact, the pressure of the uterine contraction is exerted on the fluid, and because fluid is not compressible, the pressure is equalised throughout the whole uterus and over the fetalbody, this is referred to as
the general fluid pressure. Preserving the integrity of the membranes during labour optimises the oxygen supply to the fetus and also prevents intra uterine infection.
3. Rupture of the membranes – Physiologically, the ideal time for rupture of membranes is at the end of the first stage of labour, when the cervix becomes fully dilated and no longer supports the bag of membranes with increasing force of t he uterine contraction. Membranes may however rupture days before labour begins or during the first stage of labour. Occasionally the membranes do not rupture even till the second stage of labour and they appear as a bulging sac at the vulva covering the baby’s head as the baby is born, this is referred to as ‘caul’.
4. Fetal axis pressure – With each contraction, the uterus rears forward and the force of the fundal contraction is transmitted to the upper pole of the fetus down the long axis of the fetus and is applied by the presenting part to the cervix. This is referred to as fetal axis pressure, it becomes more significant after rupture of membranes and during the second stage of labour.
MANAGEMENT OF FIRST STAGE OF LABOUR
When a patient arrives the hospital, she should be welcomed in a friendly manner and made to feel that she is expected. Reassure the patient and relatives and make patient comfortable.
A welcoming attitude and a comfortable environment will encourage couple to relax and respond positively to the forces of labour. The midwife must make an immediate assessment of whether delivery is imminent and if so, admission procedures and preparation for the birth is made
The bio data i.e Name, Age, etc of the patient should be confirmed with the patient’s chart. Gestational age, parity, history of previous and present pregnancies, weight of previous babies, full social medical and obstetric history must have been obtained and recorded in patient’s ante natal card. In case patient is un-booked, all of this information will have to be obtained afresh.
The history of labour taken by the midwife includes the following
1. The uterine contraction
2. Show
3. Rupture of membranes
4. Sleep, rest and food
– The uterine contraction
The midwife ask the woman when regular uterine contraction started, how often they are coming and if she experience backache, discomfort or pain in the lower abdomen. The severity or character of the uterine contraction should be ascertained whether it is expulsive in nature or not.
– Show
The woman is asked if she has seen show at home or if her undergarment is stained with mucoid blood.
– Rupture of membranes
Abdominal examination – The shape of the abdomen is observed by the midwife, if it is pendulous, round, small or large for gestational age. This is noted by the midwife
With the woman in a lying down position, the midwife examines the abdomen she also looks out for oedema- pretibial oedema or puffiness of the fingers or face.
An abdominal examination is conducted to determine
– The lie of the fetus
– The presentation
– The position as well as engagement of the fetal head
– The fetal heart sounds are listened to, and recorded
The abdominal examination is repeated at intervals to identify progress and recognise any deviation from normal.
Vagina examination – This is carried out to know the baseline data and also assess the cervical effacement and dilatation, presentation, assess progress and determine any deviation from normal
General management
Knowing well that labour is an event having great physiological, social and emotional meaning for the mother and her family, the midwife who is the caregiver should display tact, sensitivity, skill, imagination, patience, integrity, and respect the needs of each individual and provide a conducive environment within which each woman can labour and give birth with dignity. Good management of labour calls for a lot of understanding from the midwife. The areas of management includes the following
• Environment – The environment in which a woman delivers should be conducive physically and psychologically. The physical environment should be free from harm and infection. Facilities and necessary materials should be made available. The attitude of the staff should be welcoming and not repulsive, intimidating or abusive. Anxiety will affect the woman negatively all through the process of labour.
• Emotional support – Apart from the traditional role a midwife plays that includes being ‘with woman’. She has the role of imparting confidence, giving care to her patient and being dependable. The midwife should be tolerant, non-judgemental and being an advocate for the childbearing woman. The labouring woman must be free to ask questions and midwives must give necessary information by explaining procedures to be done and also explaining findings. Privacy must also be strictly provided for a woman in labour
• Prevention of infection – The midwife must make sure infection is reduced to the barest minimum for a woman in labour. This should start ante-natally as the woman should have been educated on the factors which affect resistance to infection, which include; nutritional status, hygiene, rest, blood, skin and membranes. Since nosocomial infection can be contacted, it is the responsibility of the midwife to make sure that high standards of cleanliness are maintained in the wards even if she does not have managerial control over domestic services. Protective materials eg gloves, apron etc should be worn by the midwife. Soiled materials, pads and body fluids should be well discarded. Invasive procedures eg vaginal examination should be reduced to the barest minimum to limit the spread of infection.
• Position and mobility – The midwife must be flexible during labour and allow the woman to adopt any position suitable for her during labour. She may walk about, rock, adopt a kneeling position or squat unless there’s a contraindication eg ruptured membrane, APH, auto cavalocclusion, narcotic analgesia etc.
• Nutrition – Different hospitals have different policies regarding feeding in labour, but a woman can take light diet in labour if tolerated. Most patients in labour have poor appetite but dehydration must be avoided at all cost. Women need energy in labour, therefore juice, tea, toast, sips of ice etc which are easily digestible can be taken to give energy. Alternatively, an intravenous infusion can be put up to provide glucose and fluid to reduce risk of conditions like gluconeogenesis and keto-acidosis.
• Bladder care – The woman should be encouraged to empty her bladder every 2 hours in labour because a full bladder may impede descent of the fetal head and inhibit effective uterine contraction. All efforts should be made to make the woman void naturally after which a catheter is passed if it fails.
• Observations – The vital signs of the woman is observed during labour to detect any deviation from normal. Pulse is taken every 1-2 hours, a rise in pulse may indicate infection, ketosis, and haemorrhage or ruptured uterus. Temperature is taken 4 hourly; a rise in temperature may suggest infection or ketosis. Blood pressure is also taken 4hourly. Hypotension may be caused by supine position, shock, or epidural analgesia. Urine must be tested for glucose, ketones and protein during labour. Ketones may occur as a result of starvation or maternal distress. Fluid balance must be maintained by keeping strict intake and output charts.
The progress of labour is monitored by noting; contractions, descent of the presenting part, vaginal examination, effacement and dilatation, flexion and rotation.
The fetal condition is also monitored during labour by assessing the fetal heart rate, fetal blood sampling, rupture of membranes-colour and quantity, signs of fetal distress are also observed eg fetal tachycardia, fetal bradycardia, and meconium stained liquor
• Relief of pain – Every labour is accompanied by a certain amount of pain. The degree of pain and the ability to withstand it vary in women. Labour can be relieved with pharmacological and non -pharmacological means of relieving pain in labour. Example, analgesics egPentazocine injection (fortwin), Pethidine etc.
• Records – Accurate record is essential to monitor progress and for early detection of complications. The midwife must keep proper records of all events- the woman’s physical and psychological condition, fetal condition etc. All the recordings should be made on a Partograph
• Parthograph
Introduction
Every normal pregnancy is expected to lead to normal labour and delivery. It is recommended that progress of labour is monitored using a partograph. Health care providers caring for women in labour are responsible for making observations and recording information on the partograph.
Definition
• A tool adapted by World Health Organisation (WHO) as a tool to monitor, document and manage labour.
• It is a managerial tool for prevention of prolonged and obstructed labour by early and timely recognition and reduce complications.
• It is also a chart of record where all labour observations are charted in a clear way and these observations are interpreted to detect abnormalities.
•
Importance
• Gives a complete picture of how the mother, baby and labour are doing.
• Provides guidelines on when labour is no longer normal and what to do.
• Helps give continuity of care.
RELIEF OF PAIN IN LABOUR
Every labour is accompanied by a certain amount of pain and discomfort. The degree of pain and the ability to withstand it vary in women. Therefore, every woman in labour should be given maximum relief from pain consistent with her personality, her safety and that of her infant.
ANATOMY OF PAIN PATHWAYS
Pain can be defined as a feeling of distress, suffering or agony caused by stimulation of specialized nerve endings. Pain stimulates pain receptors and this stimulus is transferred via specialized nerve endings to the spinal cord and from there to the brain.
Pain is felt over the anterior abdomen below the umbilicus during the first stage of labour. The referred pain felt is caused by dilatation of the cervix and lower uterine segment with each uterine contraction.
The pain pathway or ascending sensory tract originates in the sensory nerve endings at the site of trauma. The impulse travels along the sensory nerves to the dorsal root ganglion of the relevant spinal cord – the first neuron. The second neurone arise in the posterior horn, crosses over within the spinal cord and transmits the impulses via the medulla oblongata, pons varolii and the mid brain to the thalamus. From here, it transmits along the third neurone to the sensory cortex
The stretching of muscles and ligaments of the pelvic cavity and the pressure of the descending fetus during the birthing process causes to varying degree, pain in labour. This sensation is transmitted by afferent or visceral pain being caused by the stretching or irritation of the viscera.
Types of pain relief
There are two methods of pain relief in labour; Pharmacological and non-pharmacological pain relief.
1. Pharmacological pain relief – This is the use of drugs in relief of pain in labour. These drugs work by blocking the pain pathway at the nerve endings to reduce the transmission of pain to the brain thereby reducing the sensitivity of body to pain. The common drugs used include
– Opiate drugs – They are given during childbirth because of their powerful analgesic properties as they bind with receptor cells in the CNS. The receptor sites are found commonly in the dorsal horn of the spinal cord. Others are found in the midbrain, thalamus and hypothalamus The most commonly used opioids are – pethidine, diamorphine and meptazinol. Side effects includes nausea, vomiting and drowsiness and depression of baby’s respiratory centre. An antiemetic may be given to reduce the side effect
Pethidine is the most frequently used. It is a synthetic compound that acts on the receptors in the brain. The dose is 50 -150mg intramuscularly. It takes about 20 mins to have effect and last for about 2-3hours.
Diamorphine on the other hand provides effective analgesia for up to 4hrs in labour, meptazinol also given in dose of 100-150mg intramuscularly is fast acting and last for about 4hrs.
– Inhalational analgesia (Entonox)– This is made up of premixed gas of 50 % nitrous oxide and 50 % oxygen administered via the entonox apparatus. The cylinder is blue with a blue and white cylinder. It acts by limiting neuronal synaptic transmission within the CNS. It takes effect within 20 secs hence it is used before a contraction. Maximum efficiency is at about 45-50 secs at the height of contraction. The main advantage is that it is under the patient’s control. It is highly effective. It could however cause nausea and vomiting, confusion or disorientation.
– Regional epidural – This is the process of introducing local or narcotic analgesia into the epidural space of the spinal cord through a Tuohy needle for the purpose of administering regional analgesia/anaesthesia (Bupivacaine) The usual site is between the 3rd lumbar and 4th lumbar vertebrae. It works by blocking conduction of impulses along sensory nerves as they enter the spinal cord. It is the most effective way of relieving pain in labour. They are used for vagina births and caesarean section. However, it could cause dizziness or shivering and could prolong the length of the second stage.
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2. Non pharmacological pain relief – they include
– Homeopathy – It’s a way of reinforcing the body’s physiological responses. Homeopathy remedies are prepared from plant extracts and minerals
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– Hydrotherapy – This is immersion in water during labour as a means of analgesia. It is soothing and calms the nerves. Heat relieves muscle spasm and subsequently pain. It was discovered that mothers require less augmentation with hydrotherapy and the use of analgesia was consistently lower.
– Transcutaneous Electrical Nerve Stimulation (TENS) – This stimulate the production of natural endomorphinsand also its ability to impede incoming pain stimuli. (Endomorphins are opiate like substances produced naturally by the body at various points in the CNS to modulate/inhibit the transmission of pain perception in these areas) its widely used and it has the advantage of including the partner in care
– Massaging – This is a form of diversional therapy. It is done by giving a soothing backrub to the woman either by the midwife or the partner. This promotes relaxation and distracts attention from pain.
– Music therapy – Music in different forms give distraction to pain during birth. Its specially used during the early stages of labour
– Mobility and positioning – Mobility during labour has been shown to improve the woman’s experience and outcome of labour
COMPLEMENTARY CARE – labour doulas are sometimes hired by women to avoid pharmacologic pain relief during labour. The role of the doula is to provide continouslabour support and be an advocate. She specializes in assisting the woman to maintain comfort and control throughout labour and birth,
ADVANTAGES OF PAIN RELIEF
1. Reverses or reduces body’s response to labour pains
2. Patient stays awake/alert to witness labour
DISADVANTAGES
1. Likely to prolong labour
2. May likely cause low blood pressure
3. Epidurals could cause skin itching