Changes in cardiovascular dynamics during pregnancy:
the increasing demands of the growing fetoplacental unit -Normal, healthy pregnant women are able to adjust to these physiological changes quite easily. - The three peak periods of cardiovascular stress (28–32 weeks of pregnancy, during labour, 12–24 hrs postpartum) are the most critical and life threatening for women with heart disease
Recognition of cardiac compromise: -Many of the symptoms of normal pregnancy resemble those of heart disease. -The symptoms and signs of cardiac compromise include: fatigue, shortness of breath (dyspnoea), difficulty in breathing unless upright (orthopnoea) palpitations, bounding/collapsing pulse, chest pain, development of peripheral oedema, distended jugular veins and progressive limitation of physical activity.
Diagnosis -the signs and symptoms, -physical assessment -laboratory tests • full cardiovascular examination, history and assessment of lifestyle risk factors • blood tests – full blood count, clotting studies and cardiac enzymes • 12-lead electrocardiogram
-echocardiogram to look at cardiac chambers, valves and great vessels • chest radiograph to assess cardiac size and outline, pulmonary vasculature and lung fields. -Chest X-rays, with appropriate abdominal screening, should always be done • other imaging – CT chest scan or MRI
Classification of heart disease according to clinical presentation : -No limitation of physical activity. - Ordinary activity does not cause undue fatigue, palpitations, dyspnoea or angina Class II -Slight limitation of physical activity. -Comfortable at rest. - Ordinary physical activity results in fatigue, palpitations, dyspnoea or angina
Class III -Marked limitation of physical activity. -Comfortable at rest. - Less than ordinary physical activity results in fatigue, palpitations, dyspnoea or angina Class IV -Inability to carry on any physical activity without discomfort. - Symptoms of cardiac insufficiency or angina may be present even at rest, and are intensified by activity
Risks to mother and fetus The risk for morbidity and mortality depends on: (1) the nature of the cardiac lesion, (2) its affect on the functional capacity of the heart (3) the development of pregnancy-related complications such as hypertensive disorders of pregnancy, infection, thrombosis and haemorrhage. -Congestive heart failure precipitated by the altered haemodynamic state is a serious complication that may result in maternal death and can occur at any time during pregnancy -Adverse fetal effects decreased uterine blood flow or decreased maternal oxygenation.
This can lead to -spontaneous abortion - intrauterine growth restriction - fetal hypoxia -preterm birth - intrauterine death. If either parent has a congenital heart defect this may be inherited by their offspring .
Preconception care: -seek advice from a cardiologist and an obstetrician before becoming pregnant. - Preconception and antenatal counseling offer women information regarding the risks of the pregnancy to themselves and their baby.
Antenatal care: The symptoms of normal pregnancy can mimic the signs and symptoms of heart disease, e.g. dypsnoea on exertion, orthopnoea, palpitations, dizziness, fainting, a bounding pulse, tachycardia, peripheral oedema, distended jugular veins and alterations in heart sounds. - Maternal investigations should be carried out prior to pregnancy to gain baseline referral points.
Management a multidisciplinary approach involving midwives, obstetricians, cardiologists and anesthetists -During the antenatal period women with heart disease are monitored more frequently than healthy pregnant women. - The aim is to : 1-maintain a steady haemodynamic state 2-prevent complications 3-promote physical and psychological well-being. -Visits are usually every 2 weeks until 30 weeks' gestation and weekly thereafter until birth.
At each visit the woman is asked about cardiac symptoms and whether there is any limitation on her activities. Evaluation of fetal well-being includes use of: • ultrasound examination to confirm gestational age and congenital abnormality • assessment of fetal growth and amniotic fluid volume both clinically and by ultrasound • monitoring the fetal heart rate by CTG • measurement of fetal and maternal placental blood flow indices by Doppler ultrasonography
Physical and psychological care: The midwife can give advice how to modifying and adjusting physical activity during pregnancy. -In late pregnancy, women may require admission to hospital for rest and close monitoring. -Psychological support by the midwife is important.
Dietary advice: -a well-balanced diet. - Cholesterol, sodium-rich foods and salt should be restricted. -Weight gain should be monitored in these women as excess weight gain will place additional strain on the heart. - Compliance with taking iron and folic acid supplementation is important for preventing anemia
Prevention of infection: Infections often cause a pyrexia and tachycardia, which will put an added strain on the heart. - In addition the infective organism can cause endocarditis. -observe & monitor respiratory, urinary and vaginal infections and the necessity of seeking treatment as quickly as possible. -dental examination is important, which may precipitate endocarditis. - Prophylactic antibiotic therapy is recommended for women who are at high risk of endocarditis. - All invasive procedures should be using a strict aseptic technique and the number of vaginal examinations in labour should be kept to a minimum
Antithrombotic therapy: The hypercoagulable state in pregnancy increases the risk of thromboembolic disease in women who 1-have arrhythmias, 2- mitral valve stenosis 3- who have had mechanical cardiac valve replacements. -Warfarin is commonly used in the non-pregnant state but is *teratogenic in early pregnancy *a high fetal loss rate. *
It also predisposes the woman and her fetus to haemorrhage when used in the third trimester. -Subcutaneous low molecular weight heparins, such as enoxaparin (clexan ), are useful for thromboprophylaxis ,but may not be suitable for women with mechanical heart valves. -The advice of a hematologist should be sought. - thromboembolic support stockings should be worn if the woman is admitted for rest and assessment. - They should also be worn during labour and in the immediate postnatal period
Intrapartum care: the first stage of labour -good communication between the midwife, obstetrician, cardiologist, neonatologist, anesthetist. - Vaginal birth is preferred unless there is an obstetric indication for caesarean section. * The advantages of a vaginal birth are: 1-less blood loss 2-greater haemodynamic stability 3- avoidance of surgical stress and less chance of postoperative infection and pulmonary complications
monitoring the maternal condition include: temperature, pulse, respiration, blood pressure, fluid intake and urine output. - Observation of the fetal condition by electronic fetal monitoring. - Continuous electrocardiography (ECG) is recommended in nearly all cases - pulse oximetry - If oxygen saturation levels fall below 92%, oxygen therapy will be required. -ABGS -Blood and urine tests are undertaken during labour to determine the hematological and metabolic changes.
Fluid balance -intravenous fluids and fluid may need to be restricted. - Overload will lead to development of pulmonary oedema and congestive heart disease
Pain relief -the woman to use the techniques that she has learned for coping with stress. - An epidural may be the analgesia of choice as it is an effective form of analgesia that decreases cardiac output and heart rate. -Nitrous oxide ,oxygen and pethidine are usually considered safe, but it is important to consult a doctor before administering any form of pain-relieving drug to a woman with a heart condition
Positioning Avoid the supine position. -an upright position -left lateral position for some women to adopt during labour and the birth
Pre-term labor: Beta sympathomimetic drugs (ventolin & yotupar )are contraindicated in women with heart disease -they cause tachycardia and predispose to pulmonary oedema. - it is safe to use oxytocin antagonists
Induction Prostaglandins should be used with caution as they increase in cardiac output. -Oxytocin by intravenous infusion causes a degree of fluid retention so record of fluid balance .
The second stage of labour: -should be short without undue exertion -Prolonged pushing with held breath (the Valsalva maneuver), may be dangerous for a woman with heart disease. - The midwife should encourage the woman to breathe normally and follow her natural desire to push - Forceps or ventouse may be used to shorten the second stage. -Care should be taken, when the woman is in the lithotomy position, which may result in heart failure
The third stage of labour: -increased risk of postpartum haemorrhage (PPH). -Oxytocin is the drug of choice use with caution "oxytocin-induced hypotension and tachycardia in women with cardiovascular compromise" Administration should be given slowly in a dose that should not exceed 5 IU. -Ergot-containing preparations such as ergometrine are contraindicated in cardiac conditions
Postnatal care: The first 48 hrs following birth are critical for the woman with significant heart disease. -The heart must be able to cope with the extra volume of blood (auto transfusion) from the uterine circulation. - Close monitoring of haemodynamic changes is required ,the midwife should identify early signs of infection, thrombosis or pulmonary oedema -Breastfeeding should be encouraged as cardiac output is not affected by lactation ,drug therapy for specific heart conditions may need to be reviewed for safety during breastfeeding.
- need for adequate rest and a dietary intake with sufficient calories to support breastfeeding. -Discharge planning is particularly important for women with heart disease. - The woman and her partner should discuss with the cardiologist and obstetrician the implications of a future pregnancy and be given appropriate contraceptive advice .
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