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Primary Maternal Care: Hypertensive disorders of pregnancy


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Primary Maternal Care addresses the needs of healthcare workers in level 1 district hospitals and clinics who provide antenatal and postnatal care, but do not conduct deliveries. It is adapted from theory chapters and skills workshops from Maternal Care. This book complements the national protocol of antenatal care in South Africa. It covers: booking for antenatal care, assesing fetal growth and wellbeing, hypertensive disorders of pregnancy, antepartum haemorrhage, preterm labour, important medical conditions

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Primary Maternal Care: Hypertensive disorders of pregnancy

  1. 1. 3 Hypertensive disorders of pregnancyBefore you begin this unit, please take the THE HYPERTENSIEVEcorresponding test at the end of the book toassess your knowledge of the subject matter. DISORDERS OF PREGNANCY Objectives 3-1 What is the normal blood When you have completed this unit you pressure during pregnancy? should be able to: The normal systolic blood pressure is less than • Define and diagnose the hypertensive 140 mm Hg and the diastolic blood pressure is disorders of pregnancy. less than 90 mm Hg. • Give a simple classification of the hypertensive disorders of pregnancy. 3-2 What is hypertension during pregnancy? • Diagnose pre-eclampsia and chronic hypertension. Hypertension during pregnancy is defined • Explain why the hypertensive disorders as a diastolic blood pressure of 90 mm Hg or more and/or a systolic blood pressure of of pregnancy must always be regarded 140 mm Hg or more. as serious. • List which patients are at risk of A diastolic blood pressure of 90 mm hg or more developing pre-eclampsia. and a systolic blood pressure of 140 mm hg or • List the complications of pre-eclampsia. more during pregnancy is abnormal. • Differentiate pre-eclampsia from severe During pregnancy an abnormally high blood pre-eclampsia. pressure is often accompanied by proteinuria. • Provide emergency management for a patient with pre-eclampsia. 3-3 What is proteinuria? • Provide emergency management for Proteinuria is defined as an excessive amount eclampsia. of protein in the urine. Normally the urine • Manage gestational hypertension and contains no protein or only a trace of protein. chronic hypertension during pregnancy.
  2. 2. 76 PRIMAR Y MATERNAL CARETherefore, a trace of protein in the urine is not 3-6 What is chronic hypertension?regarded as abnormal. Chronic hypertension is hypertension, withProteinuria during pregnancy is diagnosed or without proteinuria, that presents duringwhen 1+ or more protein as measured with a the first half of pregnancy. There is usually areagent strip (e.g. Albustix, Labstix, Uristix, history of hypertension before the start of theMultistix, Lenstrip, etc). pregnancy.Proteinuria during pregnancy may also becaused by: 3-7 What is chronic hypertension with superimposed pre-eclampsia?1. A urinary tract infection.2. Renal disease. This is hypertension presenting during the3. Contamination of the urine by a vaginal first half of pregnancy that is complicated discharge. by the appearance of proteinuria during the second half of pregnancy. In other words it isPatients with proteinuria must be asked to chronic hypertension that is complicated bycollect a second sample, as a midstream the development of pre-eclampsia.specimen of urine (MSU). The correctmethod of collecting an MSU must be 3-8 What is eclampsia?carefully explained to the patient. Theamount of proteinuria present in the MSU Eclampsia is a serious complication of pre-must be recorded in the notes. The further eclampsia that presents with convulsionsmanagement will be dictated by the amount of during pregnancy, labour or the first 7 daysproteinuria in the MSU. of the puerperium. Convulsions can also be the result of other causes, e.g. epilepsy, but the 1+ or more protein in the urine is abnormal. possibility of eclampsia must be carefully ruled out whenever convulsions occur.3-4 What is pre-eclampsia?Pre-eclampsia presents with hypertension PRE-ECLAMPSIAand proteinuria which develop in the secondhalf of pregnancy (20 weeks or more). Pre- Pre-eclampsia is the hypertensive disorder ofeclampsia may present during pregnancy, pregnancy which occurs most commonly andlabour or the puerperium. also causes most problems for the motherPre-eclampsia is also called gestational and fetus.(pregnancy induced) proteinuric hypertension. Gestational proteinuric hypertension and chronic hypertension with superimposed3-5 What is gestational hypertension? pre-eclampsia will be discussed underIn contrast to pre-eclampsia, gestational the heading ‘pre-eclampsia’ because thehypertension is not accompanied by management is similar.proteinuria but also presents in the secondhalf of pregnancy. Should proteinuria develop 3-9 How frequently does pre-in a patient with gestational hypertension, the eclampsia occur?diagnosis must be changed to pre-eclampsia. In the Western Cape of South Africa 5–6% of all pregnant women develop pre-eclampsia. Pre-eclampsia presents with hypertension and proteinuria in the second half of pregnancy.
  3. 3. HYPER TENSIVE DISORDERS OF PREGNANC Y 773-10 Is pre-eclampsia a Pre-eclampsia may result in intra-uterine growthdanger to the mother? restriction, fetal distress, preterm delivery andYes, it is one of the most important causes intra-uterine death.of maternal death in most parts of southernAfrica. 3-15 How can the severity of3-11 What are the maternal pre-eclampsia be graded?complications of pre-eclampsia? The severity of pre-eclampsia can be graded by:The most important complications of pre- 1. The diastolic blood pressure and/oreclampsia are also important causes of systolic.maternal death during pregnancy: 2. The amount of proteinuria.1. Intracerebral haemorrhage. 3. Signs and symptoms of imminent2. Eclampsia. eclampsia. 4. The presence of convulsions.3-12 Which patients are at an increased Patients with pre-eclampsia can be dividedrisk of intracerebral haemorrhage? into 4 grades of severity:The risk of intracerebral haemorrhage is 1. Pre-eclampsia.especially high if the diastolic blood pressure A diastolic blood pressure of 90 tois 110 mm Hg or more and/or a systolic blood 109 mm Hg and proteinuria, and/or apressure of 160 mm Hg or more. systolic blood pressure of 140 to 159 mm Hg, plus proteinuria.3-13 Does eclampsia only occur at a 2. Severe pre-eclampsia.very high diastolic blood pressure? Any of the following: • A diastolic blood pressure ofNo, eclampsia can occur at a much lower 110 mm Hg or more and/or a systolicblood pressure, especially in young patients. blood pressure of 160 mm Hg or more on 2 occasions, 4 hours apart, plus3-14 Why is pre-eclampsia a danger the fetus and newborn infant? • A diatolic blood pressure ofPre-eclampsia is an important cause of 120 mm Hg or more and/or a systolicperinatal death because: blood pressure of 170 mm Hg or more on 1 occasion, plus proteinuria.1. Preterm delivery is often necessary because 3. Imminent eclampsia. of a deterioration in the maternal condition These patients have symptoms and/or signs or the development of fetal distress. that indicate that they are at extremely2. Abruptio placentae is more common in high risk of developing eclampsia at any patients with pre-eclampsia and often moment. The diagnosis does not depend results in an intra-uterine death. on the degree of hypertension or the3. Pre-eclampsia is associated with decreased amount of proteinuria present. placental blood flow. As a result of 4. Eclampsia: decreased placental blood flow the fetus Eclampsia is diagnosed when a patient with may suffer from: any of the grades of pre-eclampsia has a • Intra-uterine growth restriction or convulsion. wasting. • Fetal distress.
  4. 4. 78 PRIMAR Y MATERNAL CARE 6. Patients with a past history of a pregnancy If there is any doubt about the grade of pre- complicated by pre-eclampsia, especially eclampsia, the patient should always be placed if the pre-eclampsia developed during the in the more severe grade. late 2nd or early 3rd trimester. 7. Patients who develop generalised oedema,Patients who improve on bed rest should be especially facial oedema.kept in the grade of pre-eclampsia which theywere given at the initial evaluation. Further 3-19 What advice should be given tomanagement should be in accordance with patients at increased risk ofthis grade. pre-eclampsia?3-16 What are the symptoms and They must be told about the symptoms ofsigns of imminent eclampsia? imminent eclampsia, and advised to contact the clinic or hospital immediately, if theseThe symptoms are: symptoms appear.1. Headache.2. Visual disturbances or flashes of light seen 3-20 What special care should be given to in front of the eyes. patients at increased risk of pre-eclampsia?3. Upper abdominal pain, in the epigastrium In the second half of pregnancy, the following and/or over the liver. must be carefully watched for:The signs are: 1. A rise in diastolic blood pressure.1. Tenderness over the liver. 2. Proteinuria.2. Increased tendon reflexes, e.g. knee reflexes. 3. Symptoms and signs of imminent eclampsia. The diagnosis of imminent eclampsia is made even if only one of the symptoms or signs is Patients with an obstetric history of pre- eclampsia that developed late in the second present, irrespective of the blood pressure or the or early in the third trimester, must receive amount of proteinuria. 75 mg aspirin (a quarter Disprin) daily from a gestational age of 14 weeks. This will reduce3-17 How common is eclampsia? the risk that pre-eclampsia may develop.In the Western Cape of South Africa 3-21 What should you do if a patientthe incidence of eclampsia is 1 per 1000 develops generalised oedema,pregnancies. but remains normotensive and does not have proteinuria?PATIENTS AT INCREASED 1. She should rest as much as possible. 2. She should be followed up weekly at theRISK OF PRE-ECLAMPSIA antenatal clinic and carefully checked for the development of hypertension and proteinuria.3-18 Which patients are at an 3. She should carefully monitor the fetalincreased risk of pre-eclampsia? movements.1. Primigravidas.2. Patients with chronic hypertension.3. Patients over 34 years.4. Patients with a multiple pregnancy.5. Diabetics.
  5. 5. HYPER TENSIVE DISORDERS OF PREGNANC Y 79THE MANAGEMENT The initial management of severe pre-eclampsiaOF PRE-ECLAMPSIA and imminent eclampsia is aimed at the prevention of eclampsia and intracerebral haemorrhage.3-22 What should you do if a patientdevelops pre-eclampsia? The steps in the management of severe pre- eclampsia are:1. A patient with pre-eclampsia must be admitted to hospital. Such a patient may Step 1 safely be cared for in a level 1 hospital. An intravenous infusion is started (Balsol or2. Methyldopa (Aldomet) must be prescribed Ringer’s lactate) and magnesium sulphate is to control the blood pressure. administered as follows : All patients with pre-eclampsia must be 1. Give 4 g slowly intravenously over 10 admitted to hospital, irrespective of the level of minutes. Prepare the 4 g by adding 8 ml the blood pressure. 50% magnesium sulphate (i.e. 2 ampoules) to 12 ml sterile water. 2. Then give 5 g (i.e. 10 ml 50% magnesium sulphate) by deep intramuscular injectionTHE EMERGENCY into each buttock.MANAGEMENT OF SEVERE A total of 14 g of magnesium sulphate is,PRE-ECLAMPSIA AND therefore, given.IMMINENT ECLAMPSIA Step 2 After the magnesium sulphate has beenThe management of patients with severe pre- administered, a Foley’s catheter is insertedeclampsia and imminent eclampsia is the same into the patient’s bladder, to monitor theand consists of stabilising the patient, followed urinary referral to a level 2 or 3 hospital. Step 33-23 What are the two greatest dangers to After giving the magnesium sulphate thethe patient with severe pre-eclampsia? blood pressure must be measured again. Magnesium sulphate may cause a slightThe two greatest dangers, which are a threat drop in blood pressure. If the diastolic bloodto the patient’s life, are eclampsia and an pressure is still 110 mg Hg or more and/or theintracerebral haemorrhage. systolic blood pressure 160 mm Hg or more, oral nifedipine (Adalat) or dihydralazine3-24 How should you manage a (Nepresol) is given as follows:patient with severe pre-eclampsiaor imminent eclampsia? • Give 10 mg (one capsule) nifedipine orally or 6.25 mg dihydralazine byThe main aims of management are to: intramuscular injection.1. Prevent eclampsia, by giving magnesium • The patient’s blood pressure is taken sulphate. every 5 minutes for the next 30 minutes.2. Prevent intracerebral haemorrhage, by • If the blood pressure drops too much, decreasing the blood pressure with oral intravenous Balsol or Ringer’s lactate nifedipine capsules (Adalat) or parenteral is administered rapidly, until the blood dihydralazine (Nepresol). pressure returns to normal.
  6. 6. 80 PRIMAR Y MATERNAL CARE • If the blood pressure does not drop, 3. Convulsions must be watched for and patients who have received 10 mg the patient’s blood pressure must also be nifedipine can be given a second carefully observed. dose of 10 mg nifedipine orally if 4. If the patient begins to convulse in the the diastolic blood pressure remains ambulance, she must be given a further 2 g 110 mm Hg or more after 30 minutes. of magnesium sulphate intravenously. The If necessary, 10 mg nifedipine orally dose may, if required, be repeated once. can be repeated half hourly up to a (Make up the solution beforehand and maximum dose of 50 mg. keep it ready in a 20 ml syringe). FurtherOr maintenance doses of magnesium sulphate must be given if more than 4 hours pass • If dihydralazine was used an ampoule after the loading dose. of dihydralazine (25 mg) should be 5. If the blood pressure again rises to mixed with 20 ml of sterile water. Bolus 110 mm Hg or more while the patient doses of 2 ml (2.5 mg) are then given is being transported, you should give a slowly intravenously, at 20 minute second dose of 10 mg nifedipine by mouth intervals, until the diastolic blood or 6.25 mg dihydralazine intramuscularly. pressure drops below 110 mm Hg. Remember that, with every administrationNifedipine 10 mg capsules must always be of dihydralazine, there is a danger that thegiven orally in pregnancy and not given patient may become hypotensive. Anothersublingually (under the tongue). The 10 mg side-effect is tachycardia, and if the pulsecapsules must not be confused with Adalat rate rises to 120 beats per minute or above,XL tablets which are slowly dissolved and not further administration of dihydralazinesuitable for rapidly lowering the blood pressure. must be stopped.Step 4When the blood pressure is controlled, the THE MANAGEMENTpatient is transferred to a level 2 or 3 hospital. OF ECLAMPSIA Patients with severe pre-eclampsia or imminent eclampsia must always be stabilised before they are transferred. 3-26 What is your immediate management if a patient convulses?3-25 What can be done to ensure The management of eclampsia is as follows:maximal safety for the patient Step 1during her transfer to hospital? Prevent aspiration of the stomach contents by:1. A doctor or registered nurse/midwife should accompany the patient. • Turning the patient immediately on her2. Resuscitation equipment, together with side. magnesium sulphate, calcium gluconate • Keeping the airway open by suctioning and nifedipine or dihydralazine, must be (if necessary) and inserting an airway. available in the ambulance. Respiration • Administering oxygen. may be depressed if a large dose of Step 2 magnesium sulphate is given too rapidly. Calcium gluconate is the antidote to Stop the convulsion and prevent further be given in the event of an overdose of convulsions by putting up an intravenous magnesium sulphate. infusion of Balsol or Ringer’s lactate and giving magnesium sulphate.
  7. 7. HYPER TENSIVE DISORDERS OF PREGNANC Y 81Step 3 are good, the patient is allowed bedrest at home, under the following conditions:After the magnesium sulphate has beengiven, insert a Foley’s catheter to monitor the 1. The patient must be told about theurinary output. symptoms of imminent eclampsia. Should any of these occur, she must contact orStep 4 attend the hospital or clinic immediately.If the diastolic blood pressure is 110 mm Hg 2. The patient must be seen weekly at a high-or more and/or the systolic blood pressure risk antenatal clinic. In addition, following160 mm Hg or more, it must be reduced with the initial diagnosis, she must be seen oncedihydralazine (Nepresol). Oral nifedipine can between visits, to check the blood pressurebe used if the patient is fully conscious after and test the urine for protein.the convulsion. 3. If the patient cannot be seen more frequently, she must be given urinaryStep 5 reagent strips to take home. She must thenThe patient must now be urgently transferred test her urine daily and go to the clinic,to a level 2 or 3 hospital. should there be 1+ proteinuria or more. 4. No special investigations are indicated. Eclampsia is a life-threatening condition for 5. Alpha methyldopa (Aldomet) must be both the mother and the fetus. Immediate prescribed to control the blood pressure. management is, therefore, needed. The initial dosage is 500 mg 8 hourly. Patients with a diastolic blood pressure of3-27 What should you do if the 100 mm Hg or more and/or a systolic bloodpatient convulses again? pressure of 160 mm Hg or more, must be admitted to hospital and alpha methyldopaIf the patient convulses again, after the (Aldomet) must be prescribed. Once theconvulsions had initially been controlled by diastolic blood pressure has dropped belowthe total loading dose of 14 g of magnesium 100 mm Hg, they are managed as indicatedsulphate, a further 2 g of magnesium sulphate above.should be administered intravenously. This dosecan be repeated once more in the unlikely event 3-29 How should you monitor the fetus,of the patient having yet a further convulsion. in order to ensure fetal wellbeing? Fetal movements must be counted andGESTATIONAL recorded twice daily. A Doppler measurement of the blood flow in the umbilical artery toHYPERTENSION determine placental function should be done.3-28 What should you do if a patient 3-30 When should you deliver a patientdevelops gestational hypertension? with gestational hypertension?A patient with a slightly elevated blood If the blood pressure remains well controlled,pressure (a diastolic blood pressure of no proteinuria develops and the fetal90 to 95 mm Hg), which develops in the condition remains good, the pregnancy mustsecond half of pregnancy, in the absence of not be allowed to continue until 40 weeksproteinuria, may be managed in a level 1 when induction of labour must be or clinic. If the home circumstancesare poor, she must be admitted to hospital,for bedrest. Where the home circumstances
  8. 8. 82 PRIMAR Y MATERNAL CARECHRONIC HYPERTENSION 3-33 What special care is needed for a patient with chronic hypertension during pregnancy?These patients have hypertension in the firsthalf of pregnancy, or are known to have had 1. Any rise in the blood pressure or thehypertension before the start of pregnancy. development of proteinuria must beThey do not have superimposed pre-eclampsia. carefully looked for, as they indicate an urgent need for referral.3-31 Which patients with chronic 2. A Doppler measurement of the bloodhypertension should be referred flow in the umbilical artery to determineto a level 2 or 3 hospital? placental function should be done. 3. Postpartum sterilisation must be discussedA good prognosis can be expected if: with the patient, and is recommended1. Renal function is normal (normal serum when the patient is a multigravida. creatinine concentration).2. Pre-eclampsia is not superimposed on the 3-34 When should you deliver a chronic hypertension. patient with chronic hypertension?3. The blood pressure is well controlled (a The management is the same as that for diastolic blood pressure of 90 mm Hg or less gestational hypertension. and a systolic blood pressure of 140 mm Hg or less) from early in pregnancy.Therefore, these women can be managed at a CASE STUDY 1level 1 hospital. However, women with chronichypertension should be referred to a level 2 or A 21 year old primigravid patient has attended3 hospital for further management if: the antenatal clinic and her pregnancy1. Renal function is abnormal (serum progresses normally to 33 weeks. At the next creatinine more than 120 μmol/l). visit at 35 weeks, the patient complains that2. Proteinuria develops. her hands and feet have started to swell over3. The diastolic blood pressure is 110 mm Hg the past week. On examination, you notice or higher more and systolic blood pressure that her face is also slightly swollen. Her blood 160 mm Hg or more. pressure is 120/80, which is the same as at her4. There is intra-uterine growth restriction. previous visit, and she has no proteinuria. She5. More than one drug is required to control reports that her fetus moves frequently. the blood pressure. 1. Why is this patient at high risk3-32 Will you adjust the medication of of developing pre-eclampsia?a patient with chronic hypertension Because she is a primigravida and haswhen she becomes pregnant? developed generalised oedema over the pastYes, she must be put onto alpha methyldopa week.(Aldomet) 500 mg 8 hourly. Otherantihypertensives (i.e. diuretics, beta blockers 2. How should this patientand ACE inhibitors) must be stopped. be managed further? She should rest a lot. She also should be seen at the antenatal clinic again in a week when she must be carefully examined for a rise in blood pressure or the presence of proteinuria.
  9. 9. HYPER TENSIVE DISORDERS OF PREGNANC Y 833. What advice should this 2. On examining this patient you observepatient be given? that she has increased patellar reflexes, i.e. brisk knee jerks. How should thisShe should be told about the symptoms of observation alter her management?imminent eclampsia, i.e. headache, flashes oflight before the eyes, and upper abdominal Increased tendon reflexes are a sign ofpain. She should also be asked to count and imminent eclampsia. The diagnosis mustrecord fetal movements twice a day. If any of the be made, irrespective of the degree ofabove-mentioned symptoms are experienced, hypertension or the amount of proteinuria.or if fetal movements decrease, she must To prevent the development of eclampsia, theimmediately report to the clinic or hospital. patient must be given magnesium sulphate.4. When you see the patient a week later 3. What is the danger toshe has a diastolic blood pressure of this patient’s health?90 mm Hg, but there is still no proteinuria. The patient has severe pre-eclampsia.How should she be managed further? Therefore, the immediate danger to herThe patient has pregnancy-induced life is the development of eclampsia or anhypertension. If the home conditions are intracerebral haemorrhage.satisfactory, she can be managed with bedrestat home. The hypertension must be controlled 4. How should this patient be managed?with alpha methyldopa (Aldomet). She mustbe seen twice a week, and carefully monitored, Her clinical condition must first be detect a rise in the blood pressure and An intravenous infusion should be started andthe possible development of proteinuria. If a loading dose of 14 g magnesium sulphatethe blood pressure rises and/or proteinuria must be given. This should prevent thedevelops, she must be referred to hospital for development of eclampsia. A Foley’s catheteradmission. If the home conditions are poor, must be inserted in her bladder.she should be admitted to hospital for bed rest. 5. Is a loading dose of magnesium sulphate also adequate to controlCASE STUDY 2 the high blood pressure? No. Sometimes with severe pre-eclampsia, theAt an antenatal clinic you see a patient who is diastolic blood pressure will drop to below39 weeks pregnant. Up until now she has had a 110 mm Hg after a loading dose of magnesiumnormal pregnancy. On examination, you find sulphate has been given. In that case, no furtherthat her diastolic blood pressure is 95 mm Hg management is needed for the hypertension.and that she has 2+ proteinuria. However, if the patient’s blood pressure does not drop after administering the magnesium1. How should this patient be managed? sulphate, 10 mg (one capsule) oral nifedipine (Adalat) or intramuscular dihydralazineShe should be transferred to hospital as (Nepresol) 6.25 mg should be given.all patients with 2+ proteinuria must behospitalised. CASE STUDY 3 While working at a level 1 hospital you admit a patient with a diastolic blood pressure of 120 mm Hg and 3+ proteinuria. She is 32