Prolonged labour is by definition a labour which lasts for 24 hours or more. Modern antenatal care, together with the modern management of women in labour, has virtually eliminated a labour lasting for this length of time. During visits to the antenatal clinic a very careful note is made of any complications, so that they are corrected, and therefore most of the reasons why women used to have prolonged labours are avoided today. Caesarean section is now a completely safe operation, and induction of labour has no risk for the mother or her baby, so that the few remaining reasons for prolonged labour can be eliminated. There are several reasons, however, why a labour lasts a little longer than one might normally expect.
Delay in labour is stated to exist when progress ceases. Progress is measured by two factors—firstly, descent of the head and secondly, dilatation of the cervix. The causes of delay in labour are:
1 Faults in the forces (abnormalities of uterine contractions).
2 Faults in the passenger (abnormal or difficult position of the baby).
3 Faults in the passage (abnormality of the pelvis, vagina, pelvic floor or perineum).
Delay in the First Stage of Labour
The cause of delay in the first stage of labour is most frequently inadequate or insufficient uterine contractions, so that the time factor is not important, but if delay occurs in the presence of strong regular uterine contractions the cause must be found and remedied or Caesarean section performed.
Abnormalities in the Contractions
Hypotonic inertia. If the uterine contractions are weak and ineffective a state of uterine inertia is said to exist. In some instances the uterus never really seems to get going and the labour is never properly established The uterine contractions occur at irregular intervals every 10, or even 20, minutes and are never satisfactory or really strong, as a result of which the cervix dilates very slowly and labour becomes prolonged. This condition, known as hypotonic inertia, may be treated either by rupturing the membranes artificially in the hope that this will provoke stronger contractions, more co-ordinated uterine activity and hence more satisfactory labour, or by giving a very small dose of syntocinon in a continuous intravenous drip. Syntocinon provokes the uterus into normal rhythmic contractions and converts hypotonic inertia into normal activity, thus converting what is potentially a long labour into a normal labour. No reason is known why some labours develop hypotonic inertia. Both the mother and her baby are perfectly normal and eventually delivery proceeds quite normally without any ill effects to either the mother or her baby.
Hypertonic action is another type of abnormal uterine activity where the uterus contracts quite strongly and fiercely but for only a few seconds each time. This particular type of uterine action may be associated with a posterior position of the baby and may be accompanied by quite severe backache. The frequent, short, rather sharp uterine contractions are not as efficient as normal contractions and hence such a labour tends to be prolonged. Perhaps the most frequent cause of hypertonic action is fear. Modern antenatal care and instruction, together with modern management in labour, have greatly reduced the incidence of hypertonic inertia, but when it does occur it is treated either by sedation with fairly large doses of pethidine or similar analgesics, or by epidural anaesthesia, and either method may be combined with the administration of small doses of syntocinon by continuous intravenous drip.
It must be emphasized that long labour resulting from abnormal or inefficient uterine activity is comparatively rare today.
Abnormalities in the Passenger
Delay due to the baby is caused either by his size or the position of his head. Unless the baby happens to be 4 or 4- 5 kg., or even more, flie size does not exert very much influence on the length of labour. A big baby (say 4-5 kg.) as a first baby may cause labour to be considerably prolonged. Otherwise most of the delay caused by the baby is due to his head being poorly flexed.
Under normal circumstances the whole baby is in what is known as the foetal attitude of flexion. The spine is flexed, the head is bent down so that the chin rests on the chest and the arms and legs are flexed. In this attitude the head presents its smallest or narrowest diameter to the brim of the pelvis as well as to the birth canal. If, for some reason, the head is not well flexed then the diameters of the head that are presented to the brim of the pelvis and to the birth canal are slightly increased, so that although the baby’s head is absolutely normal in shape and size its position artificially increases the diameters which have to pass through the pelvis. This causes a certain amount of delay.
A baby’s head may be poorly flexed or actually deflexed in utero, especially in a woman who has had many children. If the head is not engaged in the pelvis before the onset of labour in a woman having her first baby, this is usually due to poor flexion of the head. Quite frequently, after the onset of labour, the head descends allowing normal flexion to occur, and labour proceeds normally. It is only when there is some difficulty in the proper flexion of the baby’s head that labour tends to be prolonged.
Posterior position. The baby normally lies With his back towards the front of the abdomen and while in this position he can assume the correct attitude of flexion. If the back lies towards the back of the mother’s abdomen, then the baby cannot lie in a properly flexed attitude and the head will be poorly flexed. It will, therefore, present a larger diameter to go through the birth canal. Such a posterior position occasionally occurs in women having their first baby and causes a rather classic series of events. The baby’s head does not engage in the pelvis at the 36th week of pregnancy; it is not engaged at the onset of labour and the membranes may rupture before labour begins with the loss of a large amount of liquor; labour may be rather prolonged, but in the majority of instances the head rotates within the pelvis to allow a normal delivery to take place; finally, in the few instances where the head fails to rotate and remains in its posterior position, a forceps delivery may be necessary.
Abnormalities in the Passage
The passage refers to die bony part of the pelvis, the soft tissue and the muscles of the pelvic floor.
The size of the bony pelvis is estimated at the first antenatal visit when, unless there is some contra-indication, an internal examination is performed and any obvious abnormality of the bony pelvis noted. If the baby’s head has not engaged in the mother’s pelvis at the 36th week of pregnancy and if it does not descend into the pelvis when she sits or stands up from a lying position, a further internal examination is performed to ascertain more accurately the internal diameters of the bony pelvis. If these are satisfactory it can be assumed with confidence that there is sufficient room in the pelvis and that the head will engage in due course. If the doctor, however, has any reason to suspect that the internal diameters of the pelvis may not be adequate then an X-ray examination may be done. If the pelvis is thought to be clinically normal the woman will be seen again at the 37th and 38th week of pregnancy and if the baby’s head will still not engage within the brim of the pelvis then the doctor may consider that an X-ray of the pelvis is justified to ascertain the relative sizes of the baby’s head and the pelvic brim. Usually only one film, an erect lateral picture, is taken from the side with the woman standing upright. This indicates not only the size of the baby’s head and the diameters of the brim of the pelvis, but also the size and shape of the sacrum and the different angles of the birth canal through which the baby has to travel. If in the doctor’s opinion the pelvis is too small then Caesarean section may be advised.
The internal size of the bony pelvis has already been proved in women who have had one baby, and provided that the previous baby was a reasonable weight and was delivered without difficulty then the pelvic measurements must be normal.
Labour may also be prolonged by the soft tissue of the pelvis. On very rare occasions the cervix is very slow to dilate, partly because it seems to become very rigid and firm, and partly because it appears to contain more fibrous tissue than usual. It is not known why this should occur, but it is a condition which may be relieved by an epidural anaesthetic.
Disproportion is a word which is commonly used, although its meaning and definition are rather uncertain. It means that there is some real or apparent discrepancy between the size of the baby’s head, being the largest part of the baby, and the size of the mother’s pelvic bones.
Abnormalities of the bony pelvis, which used to be known as contracted pelvis, are now comparatively rare. They do, however, occasionally occur, and are detected in the antenatal clinic so that the pelvis can be accurately measured both by internal examination and, if necessary, by X-ray. If the obstetrician considers that the pelvic bones are too small then Caesarean section will be performed. If he considers that although the pelvis is small it is satisfactory, he will allow labour to proceed normally, always with the reservation that Caesarean section will be performed if there is any undue delay or difficulty. The pelvis may be reduced in size by previous disease such as rickets.
Disproportion between the baby’s head and the pelvis may be caused because a baby is too big, or because the baby’s head is in the wrong position. Nature is usually very careful to ensure that small women have small babies and a woman usually has a baby of a size to fit her pelvis, regardless of the size and stature of her husband. It is unusual, therefore, for a baby to be too big, but this does occasionally happen, especially in women who are diabetic or who have a diabetic tendency. The commoner cause of disproportion is be-cause the baby’s head is in the wrong position, which usually means that it is in a posterior position or is poorly flexed. A badly flexed head usually flexes itself after the onset of labour, but if it fails to do so then disproportion may occur because a larger diameter of the head presents.
It is extremely difficult to judge disproportion before the onset of labour, since it is impossible to anticipate the strength of the uterine contractions, the ‘give’ of the pelvis or the amount that the baby’s head will flex and mould (this is the normal overlapping of the skull bones that occurs during labour and which reduces the diameter of the baby’s head by as much as i cm). Given strong uterine contractions, with adequate flexion of the head and satisfactory moulding, there are few labours that will not be brought to a normal and satisfactory conclusion.
Delay in the Second Stage of Labour
Progress in the second stage of labour is stated to stop when the head ceases to descend (the cervix already being fully dilated). Delay is said to occur in a first pregnancy if the baby is not delivered one hour after the onset of the second stage, or in a subsequent pregnancy after half an hour in the second stage. Most midwives and doctors agree that delay has occurred in the second stage as soon as progress ceases, which can usually be recognized in a much shorter interval of time and today the second stage of labour is allowed about half the time that was normally permitted about 15 years ago.
The causes of delay in the second stage are just the same in principle as those occurring in the first stage:
1 Inadequate uterine contractions (the forces).
2 A foetal head that is either too large or in the wrong position (the passenger).
3 The soft parts of the pelvis are too rigid (the passage).
Poor or inadequate uterine contractions may be the result of a. long and tiring labour, oversedation or overdistension of the uterus; gentle forceps delivery or ventouse extraction easily completes the second stage. If the fault is in the passenger then its position must be corrected, if necessary, and delivery by forceps or ventouse undertaken immediately. The head will be deeply engaged in the pelvis—if the head had originally failed to engage it would have caused delay in the first stage and a Caesarean section would have been performed before the start of the second stage.
Malposition of the Head
Persistent posterior position. When the baby’s head enters the pelvis in the posterior position it may foil to rotate through the required 18o°; the head will not descend and must be gently rotated into the correct position and forceps delivery performed.
Deep transverse arrest. Sometimes the baby’s head flexes and enters the pelvis in a posterior position and labour proceeds normally, but during the second stage of labour the baby’s head cannot complete its rotation, so that instead of the back of the head coming to lie in front, the rotation stops halfway with the baby’s head facing sideways instead of backwards. This condition is known as deep transverse arrest and no further progress will be made until the head has been gently rotated into the correct position.
Face presentation. When the baby’s head is completely extended the baby is delivered face first. If the chin is pointing forward a face presentation is unlikely to cause any delay during labour, but if the chin is pointing backwards then delay is bound to occur because the baby cannot be delivered until the head has been turned so that the chin points forwards. Just as a caput, or swelling, forms over the scalp when the head is properly flexed in a vertex presentation, so a caput forms over the face when it is presenting and it becomes considerably swollen, distorted and quite bruised. This causes no permanent damage. All the swelling and bruising disappears in three or four days and the baby’s face is absolutely normal.
Brow presentation results when the head is extended half-way between the normal vertex presentation and a face presentation. A brow presentation cannot be delivered because the diameters of the baby’s head are too big to pass through the pelvis and the baby must be delivered by Caesarean section or flexed to become a vertex pre-sentation, or extended into a face presentation.
The second stage may be unduly prolonged by resistance of the soft parts of the vagina, pelvic floor or perineum. This is particularly liable to happen in a woman over the age of 35 having her first baby, or in younger women who have indulged in a lot of sport and physical activity that has developed the muscles of the pelvic floor particularly well. It can always be overcome either by gentle forceps delivery or by an episiotomy.
Delay in the Third Stage of Labour
The third stage of labour is the time between the completion of delivery of the baby and the completion of the delivery of the placenta. This should normally take between 20 and 30 minutes, but with the modern technique of giving injections of oxytocic drugs at the time of the delivery of the baby’s head or anterior shoulder, the third stage should last between 2 and 5 minutes. If the placenta has not been delivered within this period of time and no haemorrhage is occurring, it is usual to wait for a short while. In approximately 3 per cent of deliveries the placenta will not deliver spontaneously and then a general anaesthetic is given and the placenta is stripped very gendy off the inner aspect of the uterus.
When the placenta is retained within the body of the uterus there is always a danger that bleeding may begin and therefore a very careful and constant watch is kept on the new mother until the placenta has been safely delivered. Should any excessive bleeding occur this can always be stopped by a further injection of oxytocic drug (ergometrine or syntometrine), but the presence of undue haemorrhage is an indication for immediate manual removal of the placenta under general anaesthesia.
Foetal distress is the term used when a baby is short of oxygen. There are many reasons for this but they can be broadly divided into the chronic and the acute.
The chronic, or longstanding, shortage of oxygen during pregnancy is discussed under the heading of placental insufficiency and dysmaturity. In this condition both the uterus and the baby are small and there is evidence that the placenta is inadequate.
Acute foetal distress usually occurs during labour because the uterine contractions are very frequent. When the uterus is not in labour there is no obstruction to the oxygen supply to the baby. The force of the contractions, however, obstructs the blood and oxygen supply to die placenta, but during contractions, if the placenta is healthy with good reserve, the baby will not run short of oxygen.
Acute foetal distress happens if the cord is twisted around the baby or knotted and also where haemorrhage has occurred behind the placenta. Foetal distress may also occur if the baby’s head is compressed rather tightly in the pelvis.
The signs of foetal distress are passage of meconium into the liquor, changes in the baby’s heart rate and excessive movements. Meconium is the thick, green substance normally contained in the baby’s rectum and passed only after delivery. When the baby lacks oxygen a reflex action causes passage of meconium into the amniotic fluid. This green-stained liquor is recognized as it drains out of the vagina and may be taken as a warning that the baby is becoming distressed. Some babies pass meconium at the onset of labour for no apparent reason. A woman should not be unduly worried if she notices meconium when the waters break because this sign is only significant when associated with an irregularity or fall in the foetal heart rate.
The foetal heart rate. The baby’s normal heart rate varies between 120 and 160 beats per minute and each individual foetal heart maintains a fairly constant rate, rhythm and tone. The heart may slow during contractions but as each contraction wears off it should regain its normal rate within seconds. Rates above 160 and below 120 suggest foetal distress.
Sudden and violent movements of the baby as if it were turning over and over are an indication, especially in labour, of distress of the foetus.
In recent years it has been appreciated that continuous recording of the foetal heart is more likely to detect early foetal distress than listening to the heart at regular intervals. Such recording is performed in many modern units using cardiograph machines which print out records of the heart rate and uterine contractions on a moving paper strip. Recordings are taken by harmless transducers strapped to the mother’s abdomen though better tracings of the foetal heart are obtained using a tiny clip which attaches to the baby’s scalp neither giving the baby pain nor doing it harm. If early foetal distress is detected prompt action may be taken.
Foetal Blood Sampling
In some specialized maternity units it is possible to take a small sample of blood from the baby’s head when foetal distress is suspected during labour. Examination of the oxygen content in this sample confirms or refutes the presence of foetal distress and thus enables the management of the labour to be judged more accurately.
The presence of severe foetal distress is an indication that delivery must take place as soon as possible. If the woman is in the first stage of labour and the cervix is not fully dilated, this will be by Caesarean section. If she is in the second stage, forceps or ventouse will be used for immediate delivery.
Maternal distress is comparatively rare in modern maternity units. It may be mental or physical, of which the physical may be real or potential.
Mental distress may happen when a woman who is in labour has not been properly instructed, so that she becomes afraid and it is impossible to allay her fears. This is very uncommon today because it is nearly always due to lack of co-operation and understanding in the antenatal period. It may arise when a woman knows that her baby is dead, or if she is convinced that something has gone wrong. Realphysical distress used to happen at the end of a prolonged labour which had continued for two or three days, when a woman who had become grossly dehydrated was suffering from fever and exhaustion. Such a condition is rarely seen today, partly because long labours are not allowed and partly because dehydration is prevented by the administration of intravenous fluids.
Potential physical distress. The type of maternal distress with which the doctor and midwife are concerned today is potential rather than real. Thus, in a woman who is suffering from pre-eclampsia, cardiac disease, diabetes or a raised blood pressure, it is often thought desirable, in her best interests, to shorten the second stage of labour rather than to allow the labour to pursue its normal course or to allow her the strain or exertion of pushing during the second stage. Physical strain is anticipated and avoided.
The exact history of the obstetric forceps is shrouded in mystery but they were probably invented by a member of the Chamberlen family about 1595 and kept as a secret within that family for about 130 years. It is quite astonishing that a discovery so important should be kept secret within one family for such a long time. The members of the family who used the forceps would only do so after everyone else had been sent out of the room and only then after the patient had been very heavily draped so that she should not see what was being done. The steel blades and handles were wrapped in leather so that no metallic sound should betray their presence.
Since 1730 many different types and shapes of obstetric forceps have been invented, each having minor and somewhat insignificant modifications. For very many years the obstetric forceps provided the only method of delivery if labour did not proceed naturally, but as Caesarean section has gradually become safer and more frequently performed, so the indications for performing the more hazardous types of forceps delivery have disappeared. The operation of ‘high forceps’ which carried a great risk of death or damage to the baby, as well as a risk of considerable injury to the mother, has now been completely replaced by Caesarean section. Forceps deliveries today are only undertaken when the baby’s head has descended well into the pelvis or is actually in the pelvic outlet.
The modern obstetric forceps are very simple in their construction but extremely efficient. They are so made that the blades of the forceps fit very accurately over the baby’s head and when they are properly applied the handles of the forceps come so neatly together that the blades cannot possibly damage or harm the baby’s head. In fact the forceps form a steel cage round the baby’s head to protect it from any injury that might occur by pressure from the bones of the mother’s pelvis. The term ‘prophylactic’, or protective, forceps delivery has received a great deal of attention in the United States, where quite a large number of babies at full term are specifically delivered by the forceps to protect them from injury or damage.
Many midwives and obstetricians in Great Britain are in favour of delivering premature babies by means of forceps to protect the soft and easily damaged skull.
Indications for applying the forceps are:
1 Delay in the second stage of labour.
2 Foetal distress.
3 Maternal distress.
Delay in the Second Stage
In the second stage of labour the cervix is fully dilated and the only criterion of progress is continued descent of the baby’s head. Delay in the second stage is said to occur when the head ceases to descend. The forceps can only be applied when the cervix is fully dilated. Up to a few years ago a time limit was placed on the second stage of labour and delay was said to occur in a woman having her first baby when i hour had elapsed and the child had not yet been delivered, or in a multigravid patient half an hour from the commencement of the second stage. There is today no fixed time limit and forceps delivery may be decided upon as soon as there is no further descent of the baby’s head, and this may be obvious after 10 minutes in a woman having her third or fourth child or in perhaps 30 minutes or less in a woman having her first baby. It is a matter of judgment for the midwife and doctor to decide in each individual instance.
When foetal distress occurs in the second stage, as indicated by the passage of meconium and slowing of the heart rate, speedy delivery of the baby is essential by forceps, ventouse or possibly by episiotomy.
Actual mental or real physical maternal distress rarely occurs today. Potential physical distress includes women who should not undertake the exertion of bearing down and pushing during the second stage of labour. They are relieved of this by delivery of the baby with forceps.
Several conditions must be fulfilled before the obstetric forceps can be used.
1 The cervix must be fully dilated. It is not possible to deliver the baby by the vaginal route before full dilatation of the cervix without a considerable risk of severe injury to the mother.
2 The head must be engaged in the pelvis and there must be no obvious obstruction to delivery.
3 The membranes must be ruptured. This is really only a theoretical condition because the doctor would automatically rupture the membranes immediately before applying the forceps.
4 Uterine contractions must be present, or an oxytocic drug is given at the time of delivery. This is to ensure that the uterus contracts after delivery to prevent any severe haemorrhage.
5 The bladder must be empty and as it is extremely difficult for most women to pass urine during the second stage of labour this invariably means passing a catheter to allow the urine to drain away. It is theoretically possible for a full bladder to be injured during delivery.
6 The woman must be anaesthetized (local or general).
7 There must be a reasonable prospect of delivery (e.g. no disproportion at the vaginal outlet).
The Technique of Forceps Delivery
Forceps delivery is performed under either general or local anaesthesia. Local anaesthesia may be an epidural, a caudal anaesthetic, or a pudendal nerve block. The woman is told that she is going to have a forceps delivery and the reasons for this decision are explained to her. If she is suffering from a raised blood pressure or from pre-eclampsia then she will probably have been told beforehand that the forceps will be applied shortly after full dilatation of the cervix. Anaesthesia is then induced. The exact position of the baby’s head is confirmed. If the occiput, or the back of the baby’s head, is posterior (persistent occipitoposterior position), or if the occiput is lying to one side (deep transverse arrest) then the head will be gently rotated so that the occiput comes to lie in front. Such rotation is performed either with forceps or manually. The first blade of the forceps is guided gently alongside the baby’s head so that the blade passes smoothly and easily between the baby’s head and the side wall of the vagina. The other blade is similarly inserted, using the fingers to ensure that it passes round the baby’s head and is gently inserted between the scalp and the vaginal wall. When the forceps are correctly applied the handles fit exactly.
The baby is delivered by gently pulling the forceps. Gentle traction is exerted for 30 to 40 seconds at a time, after which it is relaxed. With each gentle pull the head descends lower in the pelvis until eventually the perineum is distended, at which stage an episiotomy is performed. The mechanism of delivery with forceps is exactly the same as for spontaneous delivery—in other words the baby’s head is delivered by extending the head on the neck so that the face sweeps over the posterior vaginal wall and the perineum. As soon as the head is delivered the forceps are removed. Immediately the mouth, nose and eyes are cleaned with a sterile dry swab and the mouth and throat sucked out. If an epidural or a local anaesthetic has been administered the woman may now voluntarily deliver her baby in exactly the same way as she would do in a spontaneous vaginal delivery, because once having delivered the head the rest of the delivery is easy. Delivery is completed in exactly the same way as in a normal delivery.
The history of Caesarean section is a story of almost total failure until the beginning of this century and it is really only in the last 25 years that it has become a safe operation. The incidence of Caesarean section has gradually risen during this time and although it varies from hospital to hospital it is now fairly constant at approximately 6 per cent of all deliveries. Some of these are first deliveries and some are subsequent, or repeat, Caesarean sections. The reason for this apparently high figure is that Caesarean section is now so safe that it replaces the majority of difficult or hazardous labours. High forceps delivery, internal version, difficult forceps delivery, breech delivery either of large babies or where the mother’s pelvis may be too small, have all been replaced by Caesarean section.
For the woman herself. Caesarean section is just as safe as vaginal delivery and infinitely preferable to a difficult or complicated vaginal delivery. For the baby. Caesarean section is certainly preferable to, and invariably safer than, a difficult vaginal delivery. The factors that have contributed towards making Caesarean section safe are:
1 Improvement in surgical technique and surgical instruments.
2 The type of operation performed today is a very much better and safer operation than those previously performed.
3 Although antibiotics are not used routinely in women who are delivered by Caesarean section it is nevertheless a fact that for many years the operation was only performed on women who had been in labour for many hours and in whom the risk of infection was therefore high. Caesarean section has become a safe operation for the mother because infection can now be prevented by the use of sterile and aseptic techniques, or be treated readily should it unfortunately happen.
4 Caesarean section is occasionally performed in women who suffer from antepartum haemorrhage and in whom, therefore, blood transfusion is essential. Even in those who do not suffer from antepartum haemorrhage the blood loss at Caesarean section is invariably greater than it is at normal delivery and the ability to replace this blood loss without any danger to the mother has made the operation much more acceptable.
5 Modern anaesthesia ensures a satisfactory oxygen supply to both : the mother and her baby throughout the entire operation.
6 The rapid and great advances that have been made in the care of the new-born baby, especially of the premature baby, have meant that Caesarean section can be performed when it is urgently required to deliver premature babies.
Maternal Indications for Caesarean Section
It would be easy to Write a long list of the instances when Caesarean section should be performed in the best interests of the mother. Such a list, however, would really be meaningless because each pregnancy is treated on its own merits and each decision to perform Caesarean section is made after careful consideration of all the factors concerned. No hard and fast rules can be laid down. As the safety of the operation improves, both the frequency of the operation and the indications for its performance continue to increase.
Perhaps the most compelling and dramatic maternal indication for Caesarean section is placenta praevia. In this condition the placenta is situated below the presenting part of the baby and the gradual process of labour inevitably results in more and more bleeding from the mother’s uterus. There are, however, some de-grees of placenta praevia which are better and more safely treated by vaginal delivery.
Some other maternal indications for Caesarean section may be pre-eclampsia, eclampsia, Caesarean section performed in a previous pregnancy for disproportion, pelvic tumours such as fibroids or ovarian cysts lying below the presenting part of the baby, previous operations upon the uterus for removal of fibroids, previous damage or injury to the uterus at either curettage or abortion. A previous history of stillbirth or difficult delivery or any other obstetric cata-strophe may be sufficient indication to perform Caesarean section.
Foetal Indications for Caesarean Section
Caesarean section may be performed if it is considered to be in the best interests of the baby, either because the baby would suffer from lack of oxygen and asphyxia if not delivered immediately, or if it is considered that vaginal delivery might injure the baby. The classical foetal indication for performing Caesarean section is foetal distress during the first stage of labour, when it is feared that the baby may either become severely short of oxygen or even die from lack of oxygen if labour is allowed to proceed to vaginal delivery. Some other foetal indications are disproportion, accidental antepartum haemorrhage (in which there has been some bleeding behind the placenta but not yet of sufficient severity to kill the baby), shoulder presentation (where the baby is lying transversely in the uterus and delivery would mean a complicated internal manoeuvre) and some instances of breech presentation. Caesarean section is certainly in the best interests of the baby if the alternative procedure is a complicated or difficult vaginal delivery.
Repeat Caesarean Section
The old saying Once a Caesarean section always a Caesarean section ’ is not true today. When Caesarean section was performed in the so- called classical manner by making a vertical incision in the upper part of the uterus, then repeat Caesarean section usually had to be performed, but with the modem lower segment type of operation, delivery in a subsequent pregnancy can be normal if everything else is normal. There are several basic reasons, however, why Caesarean section should be repeated in the nest and every subsequent pregnancy: if the operation was performed because of a mechanical problem caused either by the baby being too big or by the pelvis being too small, the same conditions will apply to future pregnancies; if the first Caesarean section is necessary because of previous operations on the uterus, diabetes or other constant conditions of the mother, then obviously it will be necessary in subsequent pregnancies. There are two other main reasons why Caesarean section should be repeated, although in each instance the final decision rests with the doctor. If a woman is over 30 or if the cervix failed to dilate satisfactorily during a previous attempted labour, many obstetricians consider that a repeated Caesarean section is a wise precaution. If there is any possibility that the scar of the previous operation has failed to heal satisfactorily a repeat Caesarean section is advisable. Any evidence of infection in the uterus following a Caesarean section may indicate that the uterine scar has not healed as well as might be hoped.
Many women are worried about the limitation that Caesarean section may place upon their family and they believe that once a Caesarean section has been performed their family must be limited to two. This is not true. A woman can have as many as six or eight Casearean sections and instances have been recorded in which ten and even more have been performed. Most obstetricians consider that three Caesarean sections on any one person is a reasonable number and they will actively discourage women from having more than four children by Caesarean section.
Pregnancy after Caesarean Section
The majority of obstetricians advise that a time interval of approximately one year should elapse after a Caesarean section has been performed before the woman again becomes pregnant. It should be quickly added, however, that if pregnancy occurs within 3 months of a Caesarean section this does not by itself constitute a medical reason for its termination. The uterus heals with remarkable speed and a Caesarean section scar is completely healed 3 months after operation. Nevertheless, a woman requires time to readjust after pregnancy and delivery, and this is naturally slightly prolonged after a major operation such as Caesarean section. Caesarean section has no effect on fertility and a woman will become pregnant just as easily following the operation as she did before it was performed.
Vaginal delivery of a pregnancy subsequent to a Caesarean section must always be performed in hospital. If a woman has had a previous Caesarean section she should report to her doctor and to the hospital antenatal clinic as soon as she is certain that she is pregnant. When she visits the antenatal clinic she will be treated in exactly the same way as everyone else, except that special interest will be taken in the previous operation and the reasons why it was performed, as well as in her subsequent health and progress. The method of delivery will be discussed and if repeat Caesarean section is to be performed the reasons will be explained. If vaginal delivery is planned, the doctors will always reserve the right to perform Caesarean section at any stage should the need arise. A definite decision about the method of delivery cannot be made so early in pregnancy.
As pregnancy advances a careful watch will be kept for any evidence of a recurrence of the indications for the previous operation. After the 32nd week particular attention will be paid to the scar in the uterus from the previous operation. This is situated transversely across the lower abdomen just above the level of the symphysis pubis. A vertical or a transverse incision may be present in the skin, but the doctor and midwife are not concerned with this but with the site of the uterine incision. As the uterus grows the uterine incision will stretch and may cause some discomfort. Pain or tenderness in the uterine scar may indicate that excessive stretching is taking place and although the scar normally causes a certain amount of discomfort and tenderness it is for the midwife and the obstetrician to decide whether this amount of discomfort is normal or not. As during any pregnancy, any bleeding that occurs should be immediately reported. Any undue lower abdominal pain or discomfort should also be reported.
Labour after Caesarean Section
If it has been decided to allow a vaginal delivery it is unlikely that pregnancy will be permitted to go beyond term and it is possible that labour may be induced before the expected date arrives. The exact time and method of induction will depend entirely upon the obstetrician, the woman’s past history and the reasons for performing the previous operation, bearing in mind that no two women are identical and each is treated as a separate individual with completely separate and unrelated problems. Once labour is established it will proceed perfectly normally. Particular attention will be paid by the midwife and doctor to any vaginal bleeding or show, to the condition of the uterine scar, to the exact type of uterine contractions and whether the uterus relaxes completely in between contractions. The labour, apart from these frequent and careful observations, will be the same as any other labour until the cervix is fully dilated.
It is usually considered advisable to allow a mother only a very short time in the second stage of labour because this stage imposes a particularly severe strain on the previous Caesarean section scar. If the second stage is easy and straightforward and the head descends without any difficulty, a normal delivery may be expected, although an episiotomy will almost certainly be performed. If there is any delay or difficulty in the second stage, so that the woman is not delivered after about 20 minutes, then forceps or ventouse delivery will be conducted under general or local anaesthesia. After a vaginal delivery the third stage of labour and the puerperium will be completely normal.
Subsequent deliveries, even having achieved one vaginal delivery following Caesarean section, must be conducted in hospital. The same care and meticulous attention to detail are always bestowed even on a fifth or sixth baby following the original Caesarean section. The obstetrician always reserves the right to perform a repeat Caesarean section should he consider it necessary. If any mechanical problem develops, or should the cervix fail to dilate satisfactorily, or the baby’s head get itself into the wrong position, then Caesarean section may be repeated.
Rupture of a Previous Caesarean Section Scar
Rupture of a previous classical (vertical) Caesarean section scar is stated to have occurred after approximately 4 per cent of operations. This is a remarkably fine achievement when one considers that most classical Caesarean sections were performed under conditions vastly different from those which exist today.
Rupture of a lower segment Caesarean section scar is stated to occur in o-5 per cent of operations (i in every 200). Even so, these figures are approximately 20 years old and surgical technique and the management of the operation have advanced greatly since then. The present day figure is more likely to be o-1 per cent (1 in every 1,000) and the majority of obstetricians and midwives have never seen a lower uterine segment Caesarean scar rupture. Rupture usually results when labour begins in a woman in whom Caesarean section was previously performed because of disproportion between the baby’s head and the bones of the pelvis. The disproportion naturally recurs so that an undue strain is eventually placed upon the previous scar, resulting first in overstretching, and then in rupture.
Much care is devoted during pregnancy and in labour to the condition of the uterine scar. If undue stretching or thinning of the scar is detected, repeat Caesarian section will be recommended long before rupture occurs.
Technique of Caesarean Section
Caesarean section is a comparatively simple operation. The woman’s abdomen is shaved and, providing it is not an emergency operation, she should have nothing to eat or drink for 6 hours before it is due to begin. Premedication consists of an injection to reduce secretions from the throat and lungs as well as an antacid given orally. Sedatives that might cross the placenta and affect the baby are not usually given. A woman having a Caesarean section is thus fully conscious and aware of everything that is going on when she is taken to the operating theatre. A special pre-heated incubator is in the operating theatre, a special anaesthetic is prepared, oxygen and the resuscitation equipment for the baby are available. Besides the normal theatre staff, a midwife is present to take care of the immediate requirements of the new-born baby, as well as a paediatrician. Blood will have been taken to confirm the mother’s blood group and also to crossmatch blood should a transfusion be required. In exceptional circumstances the obstetrician may agree to a woman’s request to stay awake during the operation. Here epidural anaesthesia numbs the lower half of the body so no sensation is felt. The mother cannot see the operation but will be able to hear the baby’s first cry.
The operation is not begun until the patient has been completely anaesthetized. The incision made in the skin of the abdominal wall may be vertical (up and down in the mid-line below the umbilicus) or it may be transverse (known as a Pfannenstiel incision) extending from side to side across the lower abdomen so that, when the pubic hair regrows, the scar will be almost completely covered and virtually invisible. The muscles of the lower abdominal wall are gently separated and the abdominal cavity opened. The uterus and abdominal organs are inspected to make sure that everything is satisfactory. The bladder is then dissected free from the lower part of the anterior surface of the uterus. A transverse incision is made in the lower uterine segment extending across the uterus from right to left to divide completely the muscular wall of the uterus. The membranes are thus exposed and incised. The baby’s head is delivered and immediately his mouth, nose and eyes are wiped clean with a sterile swab and the mouth and nose sucked out to remove any fluid or mucus that happens to have collected there. Delivery of the baby is then completed by gently lifting him out of the uterus and he is immediately held upside down while his mouth and throat are again aspirated. The baby will breathe or cry almost immediately. The umbilical cord is clamped in two places and divided between the clamps. The baby is handed to the midwife for further resuscitation, if necessary, and examination by the paediatrician. As soon as the baby is delivered an injection of either ergometrine or syntometrine is given to the mother by the anaesthetist and as soon as the uterus contracts (about 40 seconds after the injection) die placenta is delivered through the uterine incision.
The incision in the firmly contracted uterus is now repaired with catgut using either two or three layers of stitches. The bladder is then stitched back over the lower uterine segment, so that the incision in the uterus is completely covered. Both Fallopian tubes and both ovaries are inspected. If everything is normal the anterior abdominal wall is sutured with catgut in four distinct layers, using different stitches for each separate layer. The incision in the skin is then closed either with individual stitches or with skin clips.
From beginning to end the operation takes between-45 minutes to one hour. The first part of the operation, that is up to delivery of the baby, usually takes about 10 minutes and the remainder of the time is spent in carefully suturing the incisions that have been made. If urgency demands it can be done in half this time.
When a Caesarean section is repeated it is performed in almost exactly the same way. The same scar is used as on previous occasions, so that any woman who has had two, three or even four Caesarean sections has only one scar. The same scar in the uterus is used as at the previous operation so that the uterine wall is not weakened by several different incisions.
On waking up following Caesarean section there will naturally be pain in the operation scar. An injection of morphine or pethidine (or similar analgesic) is given to the mother to relieve this discomfort and after another sleep she will wake up feeling much better. Within a few hours of operation she will be encouraged to start drinking and to sit up. She will at first find that movements cause discomfort in the abdominal scar, but will nevertheless be encouraged to move her legs and feet as much as possible, as movement is essential for the circulation. She will also be encouraged to cough up any phlegm or sputum from her throat or chest.
The days of abdominal binders and huge dressings have long since gone, and the incision will be covered with only a small piece of gauze strapping, or there may be no dressing at all because it will have been sprayed with a special transparent, plastic skin-like dressing. The carefully inserted stitches are sufficiently strong not to need supporting by a binder or by large dressings. If the operation has been performed in the morning the mother will probably be encouraged to get out of bed in the afternoon or evening to pass urine. This is generally easier than using a bed pan. On the day after operation she will be encouraged to get up to wash her hands and face and to clean her teeth, but the midwife will give her a blanket bath in bed. She will now be drinking a normal amount and will be having a light diet, and on the second day after operation she should be taking a full diet, sitting up, getting out of bed for the toilet and bathroom, as well as holding and starting to breast-feed her baby.
Wind pains may cause discomfort on the second or third day after operation. These are completely normal and will disappear quite quickly, or as soon as wind is passed from the rectum or when the bowels are open. A mild purgative is taken on the second evening after operation and on the third morning either a suppository or an enema is given.
The stitches or dips are removed from the abdominal skin on the fifth, sixth or seventh day according to the preference of the surgeon, and thereafter the woman is allowed in the bath or shower once or even twice a day. She will be allowed out of hospital on the tenth or twelfth day after operation.
Vacuum extraction, or the ventouse, is a method of delivery frequently used as an alternative to delivery by forceps. Its principle is very simple. When the cervix is fully dilated and the baby is ready to be delivered, a small metal cup is passed gently into the vagina and placed against the baby’s head. The cup is connected to a special vacuum apparatus and a vacuum is created within the metal cup which makes it adhere to the baby’s scalp. Gentle traction is then exerted upon the cup which in turn causes the baby’s head to descend in the pelvis and to be gradually delivered.
The ventouse has become very popular in Scandinavian countries and is being used more frequently in Great Britain where it can take the place of a simple forceps delivery, especially in association with epidural anaesthesia. The indications for using vacuum extraction are when there is delay in the second stage of labour and where an easy delivery is anticipated. Occasionally the ventouse may be used before the end of the first stage of labour in order to help dilatation of the cervix if labour is becoming unduly prolonged.
There are no real complications to the use of the ventouse. When the vacuum is applied to the metal cup to make it adherent to the baby’s scalp, the tissues of the scalp are sucked into the cup so that when the baby is delivered he has a swelling on his head which is the exact size of the cup that has been applied. The swelling is filled with tissue fluid and disappears within a few hours of delivery.
Postpartum haemorrhage is the technical term for bleeding after delivery of the baby. Almost every woman is afraid of haemorrhage. One of the first things that young doctors and midwives are taught is to-control bleeding from the uterus after delivery of the baby. This used to be quite a difficult procedure, but now it is extremely simple. The uterus obeys a very simple rule. If it is completely empty it will contract and when it has contracted it will neither bleed nor, under normal circumstances, will it become infected. In certain instances, however, the uterus fails to contract properly and therefore postpartum haemorrhage occurs. Postpartum haemorrhage should not now cause any fear because drugs are readily available that will make the uterus contract and satisfactorily control even the most profuse bleeding.
Causes of Postpartum Haemorrhage
The relaxed uterus. Occasionally, even after a normal delivery, the uterus does not contract satisfactorily and bleeding continues unless or until the uterus is made to contract into a hard ball. It will contract if it is gently massaged or if an injection of ergometrine or synto metrine (syntocinon with ergometrine) is given either into a muscle or into a vein. As soon as the uterus contracts it will stop bleeding. The uterus fails to contract because it is tired, usually as a result of a prolonged labour or because of overdistension by twins or polyhydramnios, or as a result of anaesthetic drugs or sedative drugs given during labour.
The modern practice is to give an injection of either ergometrine or syntometrine as soon as the baby’s head is crowned or as soon as the shoulders are delivered, so that the uterus contracts satisfactorily very soon after the baby has been delivered. There is then no danger that the uterus will fail to contract properly or that undue bleeding will occur. Even if an injection has not been given while the baby is being delivered, a lazy uterus can easily be made to contract satisfactorily within 30 or 40 seconds of an injection of ergometrine or syntometrine into a vein.
Retained placenta. Occasionally the placenta may not be delivered normally during the third stage. If the uterus is not empty there is always a possibility that haemorrhage may occur. In this instance an injection of ergometrine or syntometrine is given to ensure that the uterus contracts satisfactorily, first in attempt to expel the placenta and secondly to prevent any haemorrhage. If the placenta still remains within the uterus it is removed by a simple operation known as ‘manual removal of the placenta’. The newly delivered woman is anaestheti2ed and the placenta is very gently stripped away from its attachment to the inner surface of the uterus. Fibroids or any similar tumours in the uterus will not usually prevent the uterus from contracting satisfactorily after delivery. Occasionally a very large fibroid may make haemorrhage likely because it hinders uterine contraction. Instances of such large fibroids are extremely rare but when they are present any bleeding can be stopped by giving repeated injections of ergometrine or syntometrine.
Injuries to the cervix. On rare occasions, if labour has been particularly rapid and forceful, or if the baby is unduly big, a tear or laceration may damage the cervix. Small lacerations frequently happen but these are of no significance. A large laceration in the very vascular cervix, however, can cause quite severe haemorrhage. Bleeding from a small laceration of the cervix stops within a few minutes after delivery. If a large laceration is present then one or two small catgut stitches may be inserted into the cervix to repair the injury and stop the bleeding.
Lacerations of the perineum and episiotomy. A small amount of bleeding may come from lacerations of the perineum or from the site where an episiotomy has been performed. The bleeding from these injuries is usually quite small but occasionally it may be increased because of the presence of varicose veins or other large vessels in the perineum. Treatment is quite easy. Simple pressure will stop any bleeding until the injuries can be satisfactorily repaired by suturing.