Heart Disease and Pregnancy - study group statement

Consensus views arising from the 51st Study Group: Heart Disease and Pregnancy

Overarching consensus views
General

1. There should be an agreed national registry for the collection of data on pregnancy in women with heart disease.These data should be collected centrally to produce a data set that would enable a more detailed analysis of risk factors for poor pregnancy and long-term outcomes (including maternal survival and infant disability). This would greatly improve the counselling information available for women.
2. There should be recognised networks for the provision of care for women with heart disease and appropriate referral links should be established. These will need to be specifically funded as the detailed care these women need cannot be provided from routine obstetric and cardiac resources. Preconception
3. A proactive approach to preconception counselling should be started in adolescence (at age 12–15 years, depending on individual maturity) and this should include advice on safe and effective contraception. Proper advice should be given at the appropriate age and not delayed until transfer to theadult cardiological services.
4. All women of reproductive age with congenital or acquired heart disease should have access to specialised multidisciplinary preconception counselling so as to empower them to make choices about pregnancy.
5. All women with significant heart disease should be reviewed regularly to ensure that there has been a recent assessment prior to pregnancy.
6. Women with heart disease are often at increased risk when assisted conception is undertaken. The advice of the multidisciplinary team should be sought before any such treatment is commenced.
7. In counselling women about motherhood, alternatives to the woman carrying the baby herself can be considered (for example surrogacy or adoption).
8. All clinicians should be aware, and should educate others, that the majority of pregnant women who die of heart disease have not previously been identified as ‘at risk’.

Antenatal care

1. Once they are pregnant, all women with heart disease should be assessed clinically as soon as possible by a multidisciplinary team (‘the specialist highrisk obstetric team’) and appropriate investigations (such as echocardiography and magnetic resonance imaging) undertaken. Direct self-referral should be allowed, to avoid any bureaucratic delays. The core members of the multidisciplinary team should be obstetricians, cardiologists and anaesthetists but midwives (as many women with mild or moderately severe heart disease will have carefully monitored normal births), neonatologists (some women will deliver growth-restricted or preterm infants) and intensivists (some women will need intensive care) should also be involved in care when appropriate.
2. Following multidisciplinary assessment, appropriate care can be arranged at a district general hospital or tertiary unit (where the multidisciplinary team is based), according to the complexity of the heart disease, the risk assessment and the locally available facilities and expertise. (A tertiary unit can be defined as a hospital (or group of hospitals) able to provide combined obstetric, cardiological and surgical expertise in the care of women with heart disease.)
3. All pregnant women with heart disease should undergo risk stratification by the multidisciplinary team to determine the frequency and content of antenatal care.
4. Immigrants to the UK (or to other developed countries) who have not had childhood health screening are a high-risk group for undiagnosed heart disease, and any cardiovascular or respiratory symptoms should lead to careful clinical and echocardiographic assessment, with consideration of additional imaging as appropriate.
5. Women with congenital heart disease are at a relatively increased risk of having a baby affected with congenital heart disease and should be offered fetal echocardiography, performed by a fully trained fetal cardiologist.
6. There is an urgent need to develop more specialist high-risk obstetric units with appropriate multidisciplinary teams.
7. Any tertiary centre caring for pregnant women with heart disease should have facilities for prolonged high-level maternal surveillance within the obstetric unit.There should also be direct access to adult critical care facilities.

Intrapartum care

1. Management of intrapartum care should be supervised by a team experienced in the care of women with heart disease (obstetrician, anaesthetist and midwife), with a cardiologist readily available.
2. A clear plan for management of labour and the puerperium in women with heart disease should be established in advance, be well documented and be distributed widely (including to the woman herself) so that all personnel likely to be involved in the woman’s intrapartum and postpartum care are fully informed.
3. The main objective of management should be to minimise any additional load on the cardiovascular system from delivery and the puerperium.This is usually best achieved by aiming for spontaneous onset of labour, providing effective pain relief with low-dose regional analgesia and, if necessary, assisting vaginal delivery with instruments such as the ventouse or forceps, limiting or even avoiding active maternal bearing down (‘pushing’).
4. Vaginal delivery is the preferred mode of delivery over caesarean section for most women with heart disease – whether congenital or acquired – unless obstetric or specific cardiac considerations determine otherwise.
5. Induction of labour may be appropriate, to optimise the timing of delivery in relation to anticoagulation and the availability of specific medical staff or because of deteriorating maternal cardiac function. However, it should be recognised that induction of labour before 41 weeks of gestation, especially in nulliparous women with an unfavourable cervix, increases the likelihood of caesarean section.

Postpartum care

1. High-level maternal surveillance is required until the main haemodynamic challenges following delivery have passed. For particularly unstable cardiac conditions (such as pulmonary hypertension or cardiomyopathy), such surveillance may be required for up to 2 weeks. Multidisciplinary surveillance should be maintained until it is judged the woman is well enough to leave hospital. Multidisciplinary follow-up assessment should take place, as a minimum, at 6 weeks after delivery (and in cases where there are continuing concerns, at 6 months), beyond which time the woman should return to her periodic cardiac outpatient care.

Additional consensus views
General

1. If any pregnant or postpartum woman has unexpected and persistent dyspnoea or is noted to be unusually tachypnoeic or tachycardic, and pulmonary embolus has been excluded, she may have peripartum cardiomyopathy and should be investigated further by a cardiologist, and usually by echocardiography.

Preconception

1. Any cardiac surgical interventions in women of childbearing age should take into account the effect they may have on pregnancy. For example, because of the risks associated with prosthetic mechanical valves in pregnancy, consideration should be given to using tissue valves for valve replacement.
2. Preconception assessment and risk stratification for women with pre-existing heart disease can be refined by cardiopulmonary exercise testing (including maximum oxygen uptake).
3. Contraceptive choice for women with heart disease should be tailored to the particular patient, taking into account any increased risks of thrombosis or infection associated with the various contraceptive methods and their interaction with the various heart lesions.
4. A key requirement for contraception is efficacy. Unlike healthy women who use contraception for family spacing, the consequences of contraceptive failure can be fatal for women with severe heart disease. Subdermal progestogen implants (such as Implanon®) and progestogen-loaded intrauterine devices (such as Mirena®) are the most efficacious and are also the safest methods for most women with significant heart disease.
5. In the event of unprotected sexual intercourse, women with heart disease should be aware that emergency contraception that is known to be safe for women with heart disease is available. Urgent access to termination of pregnancy should be readily available.

Antenatal

1. Levels of mitral and aortic stenosis that are not problematic in non-pregnant women may be poorly tolerated in pregnancy. Reduction of heart rate is often the key to successful management, especially in stenosis of the mitral valve. Beta blockers are useful in this context.
2. Cardiac surgery during pregnancy should only be considered for women who are refractory to medical treatment or when there is no catheter-based interventional alternative. Percutaneous catheter interventions are safe and effective in the treatment of coronary disease and mitral and pulmonary valve stenosis. In contrast, balloon dilatation for aortic valve disease should only be considered for highly selected cases as it carries a higher risk and a lower success rate. Such interventions in pregnancy should only be performed by experienced operators and radiation exposure should be minimised. If cardiac surgery requiring the use of cardiopulmonary bypass does need to be performed, consideration should be given to early delivery of the fetus if it is viable. If cardiopulmonary bypass is necessary, the deep hypothermia and low perfusion pressure associated with the standard techniques carries a 30% risk of fetal mortality. In the interests of the fetus, if possible, hypothermia should be avoided and perfusion pressures kept as high as possible.With these adjustments, fetal mortality can be as low as 10%.
3. In pregnancy, if there is clinical evidence of acute coronary insufficiency or myocardial infarction, coronary angiography is appropriate. The radiation exposure of the fetus is not sufficient to contraindicate this essential diagnostic procedure. The first choice for treatment of acute coronary syndrome in pregnancy is percutaneous catheter intervention.
4. Only centres with experienced teams and expertise in pregnancy and heart disease should carry out such surgical or catheter-based procedures, except in situations where transfer to such a centre would entail a greater risk.
5. Women with pulmonary arterial hypertension – irrespective of aetiology – should be advised of the very high risks of pregnancy (about 30–50% mortality) and be given clear advice about contraception. For some of these women, pulmonary arterial vasodilator therapy during pregnancy and the puerperium may improve the chances of maternal survival.
6. Tertiary units should offer a hotel facility to enable women who live some distance from the hospital to stay on site, to avoid (a) a delay in receiving appropriate care when they go into labour and (b) the need to induce labour solely to avoid this risk.
7. Screening efficiency would be improved if fetal cardiac ultrasound screening were offered on the basis of a nuchal translucency thickness exceeding 3.5 cm, as well as on the basis of family or personal history.
8. Audited training programmes in fetal cardiac scanning for ultrasonographers are advised in order to improve detection rates of fetal heart disease at the 20 week anomaly scan.
9. The threshold for starting thromboprophylaxis should be lower for pregnant women with heart disease than for the same conditions in non-pregnant women.
10. Thrombolysis may cause bleeding from the placental site but should be given in women with life-threatening thromboembolic disease or acute coronary insufficiency.
11. There is currently no ideal regimen of anticoagulation in women with mechanical heart valves in pregnancy.Women should be offered a choice between the higher rates of fetal loss associated with the use of warfarin and the higher risk of maternal valve thrombosis with subcutaneous heparin.
12. Low-dose aspirin (75–150 mg daily) is a safe and possibly effective adjunct to low molecular weight heparin in pregnant women with mechanical heart valves or an otherwise increased risk of intracardiac thrombosis.
13. In pregnant women with mechanical heart valves who elect to use subcutaneous heparin, the dose of low molecular weight heparin should be at therapeutic levels and guided by monitoring of antifactor Xa activity at least monthly.We suggest a peak (3–4 hour post-dose) level of at least 1.0 iu/ml and a trough level of at least 0.5 iu/ml. It might be possible to reduce the risk of valve thrombosis (currently estimated to be about 10%) by using higher doses but this remains speculative.
14. In women on beta blockers (for example for the treatment of systemic hypertension or to reduce the risk of arrhythmia) there is a small increased risk of intrauterine growth restriction and fetal growth should thus be monitored regularly, using ultrasound measurement of fetal abdominal circumference, if there is any clinical suspicion of poor growth.
15. All pregnant women whose condition places them at risk of aortopathy (such as those with repaired coarctation, Marfan syndrome or aortopathy associated with bicuspid aortic valve) should be made aware of the symptoms of acute dissection and be advised to seek urgent help if they experience any of them.
16. Every attempt should be made to establish the details of the cardiac diagnoses and any previous cardiac surgical or catheter-based procedures before or at preconception counselling, as this will enhance opportunities for optimising cardiac status during pregnancy.
17. When planning care, specific instructions should be recorded regarding intrapartum antibiotic prophylaxis.There is currently no evidence that prophylactic antibiotics are necessary to prevent endocarditis in an uncomplicated vaginal delivery. However, prophylactic antibiotics should be given in all cases of operative delivery and to women at increased risk,such as those with mechanical valves or a history of previous endocarditis. Prophylactic antibiotic cover should also be given before any intervention likely to be associated with significant or recurrent bacteraemia.The possibility of endocarditis should also be considered in any woman with a cardiac defect who has positive blood cultures.
18. Pregnant women with previous Kawasaki disease and coronary artery aneurysm (with or without coronary artery stenosis) should be given antiplatelet and/or anticoagulant thromboprophylaxis.
19. Timely restoration of sinus rhythm is strongly advisable in pregnant women with tachyarrhythmias and underlying heart disease. Direct current (DC) cardioversion is safe, although attention should be paid to airway management because of the risk of aspiration/regurgitation of gastric contents, and care should be taken to avoid the supine position with its accompanying risk of aortocaval compression. Careful fetal monitoring is also advisable.

Intrapartum

1. Care should be delivered by designated professionals as part of the multidisciplinary team.
2. With any surgical intervention, meticulous attention must be paid to haemostasis to avoid haemorrhage, which can cause marked cardiovascular instability in pregnant women with reduced cardiac reserve.
3. In the management of the third stage of labour in women with heart disease, bolus doses of oxytocin can cause severe hypotension and should thus be avoided. Low-dose oxytocin infusions are safer and may be equally effective. Ergometrine is best avoided in most cases as it can cause acute hypertension. Misoprostol may be safer but it can cause problems such as hyperthermia and data are still limited in this population. It should be used only if the benefits outweigh any potential risks.At caesarean section, uterine compression sutures may be effective in controlling uterine haemorrhage due to atony, and may allow the avoidance of any uterotonic agent.
4. Regional or general anaesthesia for caesarean section should be used in such a way as to optimise cardiovascular stability and should only be given by anaesthetists experienced in their use in pregnant women with heart disease.
5. In all high-risk pregnancy centres, guidelines should be in place (and regularly rehearsed) for dealing with cardiac arrest. Regular staff attendance at adult and neonatal resuscitation courses should be mandatory. All equipment, including bleep systems, should be serviced and checked regularly to ensure operational efficiency.

Puerperium

1. Angiotensin-converting enzyme (ACE) inhibitors are safe to use in breastfeeding mothers. This knowledge should be more widely disseminated and appreciated.
2. Because of the increased risk of postpartum haemorrhage in women with heart disease who are anticoagulated, the introduction or reintroduction of warfarin should be delayed until at least 2 days postpartum. Meticulous monitoring of anticoagulation is essential.