Another aspect of antenatal care is the identification of problems in the present pregnancy, both by history and clinical examination. Symptoms of nausea, abdominal pain, vaginal discharge or bleeding should be elicited, and further investigations done where necessary. It would be impossible in a chapter like this to detail abnormalities to be sought, but some important ones will be mentioned.
Pre-eclampsia
This condition has many names, but pre-eclampsia does at least give one characteristic of the disease - the fact that it may lead to convulsions. Traditionally, pre-eclampsia was defined as the presence of two signs from the triad of oedema, hypertension and proteinuria, but is now realized that oedema is very common in normal pregnancy and hypertension with significant protein-uria are more reliable signs. The disease has wide-spread effects (cardiovascular, renal, hepatic, cerebral, haematological, uterine and placental), but aetiology is unresolved. It is usually a disease of the primigravid pregnancy, and has serious complications both for mother and fetus.
The aim of antenatal care is early diagnosis and appropriate management of the pregnancy, to prevent eclampsia and other maternal complications, and intra-uterine death or morbidity ·of the fetus. Increased rest reduces the progress of pre-eclampsia and so it is important to detect hypertension early and to advise rest and more frequent visits to the antenatal clinic for review. Such mothers could also be referred for specialist care. The mother may need to be admitted to a maternity village, a health centre or a hospital for rest.
Unfortunately, many women do not present to the
health service until pre-eclampsia is already severe i.e.
a blood pressure of 160/110 or over, heavy proteinuria, oliguria, cerebral or visual disturbances and pulmonary oedema or cyanosis. The principles of management of severe pre-eclampsia are the same, and it is imperative that all levels of staff should treat the condition as an emergency and admit the patient to hospital as soon as possible.
The steps in management are:
• maintenance of an airway;
• treatment of convulsions;
• control of blood pressure;
• stabilization of mother;
• delivery of infant.
The treatment of convulsions should commence at the point when the patient meets the health service.
Maternity assistants can start treatment with either magnesium sulphate or diazepam (choice depending on local policy) intravenously or intramuscularly, while they accompany the patient to hospital. Treatment should then be continued and monitored carefully in hospital. These drugs may reduce the blood pressure to some degree, but hypotensives are usually needed as well. The most commonly used drug is hydrallazine, either in intermittent or continuous intravenous dosage. As it may cause a rapid fall in blood pressure, close monitoring is essential. When the mother is fairly stable (usually 2-4 hours after admission) delivery should be expedited either by induction of labour or Caesarean section where necessary. These patients need the most experienced personnel to give the anaesthetic and intensive care should be continued for some days.
Antepartum haemorrhage
The three common causes for bleeding from the genital tract after the 28th week of pregnancy are placenta praevia, abruptio placentae and bleeding of undeter-mined origin. Fetal mortality is high in all.
The most common mode of presentation is slight bleeding without pain or shock. These patients have to be regarded as cases of placenta praevia until proved otherwise, and need hospital admission because of the danger of further bleeding. Following admission the pregnancy should be assessed carefully, a haemoglobin estimation should be performed, prophylactic or therapeutic haematinics given, and every effort made to obtain compatible blood in case transfusion is necessary. Vaginal examination should not be performed. Two or three days after cessation of
The present pregnancy 145
bleeding a speculum examination should be performed to exclude any incidental cause of bleeding like carcinoma of the cervix. The next step is to localize the placenta by whatever method is available. Ultrasound is the most effective and least invasive method, but care should be taken in interpretation of reports. If placenta praevia can be excluded, the patient can usually be discharged, but she must still be considered a high-risk patient. If a placenta praevia is present, the woman must stay in hospital until 38 weeks, when a vaginal examination is performed under anaesthesia, followed by surgical induction or Caesarean section. If no method of placental localization is available, the patient should ideally stay in hospital until 38 weeks, when she can be examined under anaesthesia and the placenta located digitally. There will be a few cases of placenta praevia who cannot be managed conservatively because of the quantity of bleeding, and these need to be delivered urgently by Caesarean section.
Some women will be seen with clinical signs of abruptio placentae, i.e. bleeding from separation of a normally situated placenta. This bleeding may be completely revealed when the degree of shock corresponds to the amount of bleeding, concealed when the patient may be very shocked with no apparent blood loss, or commonly a mixed pattern may occur.
Typically, in abruptio placentae the dominant symptom is pain, and the patient may be pale and shocked when she arrives. A normal blood pressure may be deceptive as the pre-abruptio blood pressure may have been raised. The abdomen will be tender, the uterus woody hard, the fetal parts not palpable and the fetal heart usually not heard. Active management is imperative, and should include sedation (with morphine), rapid assessment of general condition, review ofhaematological state (including haemoglobin, fibrinogen titre, presence of fibrinolysis) liberal trans-fusion with central venous pressure monitoring in severe cases, and induction of labour. In the rare case where the baby is alive and not too preterm, a Caesarean section may be indicated. During labour, progress must be assessed by regular vaginal examina-tion, as monitoring uterine contractions is usually impossible. Oxytocin infusion may be necessary, and if there is no progress Caesarean section may be the best management, even with a dead baby. Whatever the method, postpartum haemorrhage is a real hazard, and everything possible should be done to prevent it and minimize its effects. Transfusion is often inadequate even when there is no scarcity of blood, and patients need haematinics for varying periods of time to restore iron stores. It is important too, that they do not embark upon another pregnancy too soon.
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Hydramnios, malpresentation, unstable lie and multiple pregnancy
Antenatal clinic visits give the opportunity for regular abdominal palpation and the diagnosis of hydramnios, malpresentations, and multiple pregnancy.
The official definition of hydramnios is over 1500 ml liquor, and if it is diagnosed, associated abnormali-ties of the fetus, such as multiple pregnancy, fetal abnormality and hydrops should be sought and confirmed by X-ray or sonar. Maternal diabetes or chorioangioma of the placenta may be associated too.
Occasionally the mother may need to be admitted for rest because of severe hydramnios, and if discomfort is marked, liquor may have to be removed by amnio-centesis. The labour is high risk, and the attendant may have to deal with malpresentation, prolapsed cord, multiple pregnancy and postpartum haemorrhage.
Oesophageal atresia or oesophageotracheal fistula may be present in the neonate, and should be excluded soon after birth by passing an endotracheal tube.
Breech presentation
The incidence of breech presentation is 2-3 per cent and the two common aetiological factors are pre-maturity or any factor that prevents the spontaneous version which has normally occurred by about the 34th week of pregnancy. Because of the hazards of breech delivery, there is a natural desire to avoid it if at all possible, and this has led to the practice of external cephalic version. This is usually done around 34 weeks if there are no contra-indications such as hypertension, antepartum haemorrhage and previous Caesarean section. Despite the satisfaction of doing a successful external cephalic version, it is not a procedure without complications and there is no evidence that it reduces the frequency of breech presentation at the beginning of labour.
Breech delivery
If perinatal mortality and morbidity are to be avoided, breech deliveries must be conducted by experienced personnel and Caesarean section should be performed if breech presentation is accompanied by any other complications, e.g. contracted pelvis, a large baby, footling presentation or a bad obstetric history. It is therefore imperative that breech presentation is diagnosed antenatally so that the decision to deliver vaginally or by Caesarean section can be taken before the onset of labour. Prolapse of the cord is more common in breech presentation and vaginal
examina-tion performed when the membranes rupture. Delay in the first stage may be a sign of disproportion and abdominal delivery should be done sooner rather than later. It is often difficult to establish when the second stage commences because parts of the breech can pass through an undilated cervix and give the mother a desire to push. Therefore, the mother should be discouraged from pushing until the anterior buttock is fully visible, or until vaginal examination has verified full dilatation with the presenting part below the ischial spines. Ideally an epidural anaesthetic should be administered during the first stage and if possible an anaesthetic should be available in the delivery room during the second stage in case one is required. If there is non-descent of the breech in the second stage, the only management is Caesarean section. A pudendal block should be performed for breech delivery if there is no epidural anaesthesia, and this facilitates timely episiotomy. Delivery as far as the umbilicus should be spontaneous, the legs can then be flexed and delivered and a loop of cord brought down. When the anterior scapula is visible, the arms can be flipped out, the back gently rotated uppermost and the baby allowed to hang by its own weight. The head will flex and descend slowly and when the nape of the neck is showing the attendant should extend the infant upwards by its ankles and deliver the head slowly and carefully. Many prefer to use Wrigley's forceps to control the delivery of the head, especially where there is no epidural anaesthesia, and this allows an assistant to suck out the upper respiratory tract before the baby breathes. A problem may be extended arms, and these should be delivered by the well-documented Lovset's manoeuvre.
The worst difficulty is failure of the head to descend and this can be due to an incompletely dilated cervix, poor flexion of the head, previously unrecognized dis-proportion, or hydrocephalus. Flexion of the head, and downward traction using the Mauriceau -Smellie-Veit manoeuvre may succeed. Occasionally there is a place for cervical incision or emergency symphysiotomy but this should only be performed by experienced people.
Hydrocephalus will often necessitate craniotomy to effect delivery.
Unstable lie and other malpresentation
Another finding in the antenatal period which is likely to end in malpresentation is a transverse or an unstable lie, and these are more common in grand multiparous patients. If repeated attempts at external cephalic version do not result in stabilization, it is wise to admit the patient at about 38 weeks to a maternity village or hospital where medical care is quickly available should
she go into labour with uncorrected malpresentation.
External cephalic version in very early labour, when the uterus has developed some degree of tone, may be effective and result in an uncomplicated labour. Should the membranes rupture in a case like this, vaginal examination should be done immediately to exclude a prolapsed cord. If a prolapsed cord is found, or if a shoulder presentation persists, Caesarean section is the only safe course. Some centres use stabilizing induction in the management of these cases, i.e. uterine activity is induced with syntocinon after 38 weeks and the membranes are ruptured after the onset of regular contractions to release enough liquor to stabilize the presenting part; following this labour should progress normally. It is essential that such a procedure is monitored very closely by experienced staff. Should a woman arrive in labour with an arm or shoulder presentation, she should be transferred to hospital and a Caesarean section be performed if the baby is alive. If the baby is dead, decapitation with an instrument like the Blond-Heidler saw or large scissors is preferred.
The risk of ruptured uterus must always be considered in these cases.
Face and brow presentation are only rarely diag-nosed in the antenatal clinic, so these presentations are usually encountered for the first time in labour. When diagnosed, the mothers should be transferred to a centre where Caesarean section is possible, as this is the only management in brow presentation, and is often needed in a persistent mento-posterior face present-ation. Mento-anterior presentations may deliver spon-taneously, but may also need forceps delivery.
Multiple pregnancy
The average incidence of multiple pregnancy is about 1:80, but it varies in different communities and racial groups. The diagnosis is suspected when the uterus is large for dates, or when three fetal poles are palpated, but it is imperative to confirm the suspicion with either X-ray or sonar. Multiple pregnancy is associated with many complications of pregnancy, e.g. exaggerated symptoms like tiredness, vomiting or oedema, anaemia (including folic acid deficiency) and other nutritional deficiencies, pre-eclampsia, hydramnios, malpresent-ations and preterm labour. Increased rest should be advised during pregnancy and the mother may have to be admitted for this. The labour, too, is high risk and wherever possible should be in hospital.
There is no reason why the management of the delivery of the first twin should differ from the singleton, but methodical steps should be taken to ensure the safe delivery of the second. The comments
The present pregnancy 147 about anaesthetic requirements for breech delivery apply also in multiple pregnancy. Once the first twin is delivered, and the cord clamped in the usual way, the abdomen should be palpated to ascertain the lie and the presentation of the second twin, and an external cephalic version done if necessary. Artificial rupture of the membranes should follow, and sometimes synto-cinon infusion is needed to initiate contractions. If delivery is at all delayed in a vertex presentation, forceps delivery or vacuum extraction should be performed. In a second twin, internal podalic version and/or breech extraction are not dangerous because of the amount of room available in the uterus, and because the membranes are only recently ruptured. However, a second twin, larger than the first, could cause unexpected trouble. As postpartum haemorrhage is a very real hazard in twin delivery, intravenous ergometrine should be given prophylactically. When a patient is admitted with a retained second twin, an experienced person should make the necessary decisions regarding delivery, taking into consideration the mother's general condition, the lie and presentation of the fetus and whether it is alive, the duration of ruptured membranes and the dilation of the cervix.
Intrauterine growth retardation
Intrauterine growth retardation is never an easy diagnosis in the antenatal period, and it becomes even more difficult when mothers are unsure of their dates and facilities, e. g. sonar for establishing gestational maturity, are not available. The most widely used definition is a weight below the third centile and this is one of the three main causes of perinatal mortality.
Though intrauterine growth retardation has many known causes e. g. socio-economic circumstance of mother, malnutrition, pre-eclampsia, hypertension, abruptio placentae, smoking and infections, the aetiology in the majority is unknown.
Clinical suspicion of intrauterine growth retardation may occur when a mother loses weight or fails to gain weight, when a uterus appears small for dates or when there is oligohydramnios. Symphysis-fundus measure-ments are helpful, especially if serial and carried out by the same person. Failure in growth may be confirmed by serial ultrasonography and this may also identify a fetal abnormality. Once suspicion is aroused the fetus is in the high-risk category, and every effort should be made to establish whether it is likely to die in utero if there is no intervention. Available methods in hospital will vary from fetal movement counts to antenatal cardiotocography to oestriol assays and other estimates
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of placental function, but without these one has to rely on clinical estimate of growth and size.
Management is not easy, especially where facilities are limited. Every effort should be made to treat any identifiable underlying maternal condition and to increase blood flow to the uterus by bed rest. Ifpossible, management is then conservative until about 37 weeks, when delivery can be induced. A reduction in fetal movements or serial oestriols will point towards early delivery, as will a critical fetal reserve pattern (reduced baseline variability, absence of accelerations and repeated late decelerations in response to Braxton-Hicks contractions) on cardiotocography. In this group continuous observation in labour is the ideal, and the best technology available should be used. The quality of neonatal intensive care available will be a guide as to how early in pregnancy a fetus can be delivered and survive.