The pearls for optimal intrapartum care in women with cardiac disease

Abstract

Cardiac disease during pregnancy is one of the leading causes of maternal mortality and morbidity in both the UK and the USA. Labour, delivery, and the initial postpartum phase are characterised by significant haemodynamic alterations that play a significant role in the clinical deterioration observed in women with heart disease. Heart failure, arrhythmia, and myocardial ischaemia can occur in women with high-risk cardiac lesions during labour. The cardio-obstetric multidisciplinary team, after risk stratification, should establish an individualised cardiac care plan that incorporates patients’ preferences. This care plan should address the location, mode, timing of delivery, monitoring, analgesia, and anaesthetic options for operative intervention, uterotonics that may be administered, emergency contact numbers for relevant personnel along with appropriate postpartum care. High-risk patients need to be delivered in tertiary units. Clear haemodynamic objectives should be established along with a postpartum contraception plan with information cascaded to community midwifery teams and primary care providers to ensure surveillance and continuity of care. Co-ordinated multidisciplinary care can enhance preparedness for obstetric and cardiac emergencies, thereby decreasing morbidity and mortality associated with heart disease in pregnancy during childbirth.

Introduction

The intrapartum period, encompassing labour, delivery, and the immediate postpartum period, represents a critical time for women with heart disease. This period carries substantial risks and can lead to considerable maternal morbidity and mortality, particularly among those with high-risk cardiac conditions. The CARPREG II study highlighted that cardiac arrhythmia and heart failure (HF) were the two most common cardiac complications encountered in women with heart disease in pregnancy during labour. ¹ Confidential enquiries into maternal deaths, as reported by the Mothers and Babies: Reducing Risk through Audits and Confidential Enquiries (MBRRACE) across the UK, indicate that ∼40% of maternal deaths attributed to heart disease occur within the first six weeks postpartum, with 15% occurring on the day of delivery. ² Awareness of the haemodynamic changes during birth along with the specific cardiac conditions that contribute to morbidity, can assist healthcare professionals to devise strategies that focus on appropriate location, mode, timing of delivery, and intrapartum monitoring with effective analgesia to mitigate some of these risks during birth.

This review aims to provide a practical overview of the obstetric, anaesthetic, and cardiac considerations for pregnant women with heart disease at birth, as well as during the immediate postpartum period.

Physiological changes of pregnancy during labour

During the first stage of labour, uterine contractions contribute to a 25% increase in cardiac output (CO), due to an increase in stroke volume from uterine blood flow that is directed to the systemic circulation, while pain from these contractions leads to an increase in the sympathetic drive. This contributes to a significant increase in heart rate (HR) and a rise in systolic and diastolic blood pressure (BP) by 15%–25%. These effects may be exacerbated by patient anxiety and hyperventilation, which not only increase oxygen demand and reduce supply but also elevate aortic shear stress.

During the second stage of labour, the Valsalva manoeuvre induces additional variations in HR, BP, and CO, alongside fluctuations in intrathoracic pressure. CO peaks to over 50% above pre-labour values. In the third stage, following the delivery of the fetus and placenta, there is a release of aortocaval compression and autotransfusion from the placental circulation, further boosting CO, which peaks at ∼75%–80% of pre-labour values by 12–48 hours postpartum. ³ These changes may further be influenced by any on-going haemorrhage and infection. These haemodynamic alterations in women with heart disease create an environment conducive to adverse cardiac events during the intrapartum and the immediate postpartum period (Figure 1).

Figure 1.

Factors contributing to adverse cardiac events during labour in women with heart disease.

Location of delivery and cardiac care plans

Low-risk (mWHO I/II or those with CARPREG II score ≤ 2) women may deliver at a local hospital with input from a maternal medicine network, whilst high-risk (mWHO II-III/III/IV or CARPREG score > 3) women should deliver at tertiary units that have 24/7 access to the cardio-obstetric team and cardiac care facilities ⁴ (Table 1).

Table 1.

Modified World Health Organisation (mWHO) classification of maternal cardiac risk. ⁴

Class	Risk and maternal cardiac event rate	Cardiac lesion	Care during pregnancy and location of delivery
I	No increased risk of maternal mortality and no/mild increase in morbidity. (2.5%–5%)	Uncomplicated pulmonary stenosis, patent ductus arteriosus. Successfully repaired simple lesions (e.g. atrial or ventricular septal defects)	Local hospital Input from the local maternal medicine network and pregnancy heart team a if necessary
II	Small increase in maternal mortality and moderate increase in maternal morbidity. (5.7%–10.5%)	Unoperated ASD or VSD Repaired tetralogy of Fallot Turner syndrome without aortic dilatation Most arrhythmias	Local hospital Input from the local maternal medicine network and pregnancy heart team a if necessary
II and III	mWHO Class II or III (depending on the individual). (10%–19%)	Mild left ventricular impairment Hypertrophic cardiomyopathy Marfan syndrome without aortic dilatation	Dynamic assessment Assess risk versus benefits of delivery at local versus tertiary unit Regular input from pregnancy heart team a
III	Significantly increased risk of maternal mortality or severe morbidity. (19%–27%)	Mechanical heart valve. Systemic right ventricle. Fontan circulation Unrepaired cyanotic heart disease. Aortic dilatation 45–50 mm (40–45 mm in Marfan syndrome).	Tertiary unit Regular input from pregnancy heart team a
IV	Extremely high risk of maternal mortality or severe morbidity. Pregnancy contraindicated, termination should be discussed if becomes pregnant, if she wishes to continue with the pregnancy. Care as per Class III. (40%–100%)	Pulmonary arterial hypertension Left ventricle ejection fraction < 30%, New York Heart Association Class III-IV Previous peripartum cardiomyopathy with any residual left ventricle impairment Severe mitral or aortic stenosis Aortic dilatation > 50 mm (> 45 mm in Marfan syndrome)	Tertiary unit Regular input from pregnancy heart team a

^aPregnancy heart (cardio-obstetric) team – obstetrician, cardiologist, obstetric anaesthetist, cardiac anaesthetist, maternal-fetal medicine specialist, haematologist, neonatologist, cardiac surgeon, and midwife.

Healthcare professionals responsible for the care of women with cardiac conditions should have access to a personalised intrapartum cardiac care plan developed by the multidisciplinary cardio-obstetric team comprising of obstetrician, obstetric anaesthetist, midwifery, cardiology, and other team members as necessary. ⁵ The care plan must delineate the delivery mode, its location, and the personnel to be notified upon the woman's arrival at the delivery unit. It should include recommended monitoring, essential investigations upon arrival, analgesic and anaesthetic options, considerations for caesarean birth, preferred uterotonics, vasopressor agents, and any medications that need to be avoided. It should also outline postpartum care, a contraception strategy, and emergency contact numbers for relevant personnel if there is a cardiac emergency. ⁵ A copy of the care plan should also be provided to the woman as well in accordance with MBRRACE-UK guidelines, particularly if she presents to a different maternity unit or in an emergency.^2,4

Mode of delivery

Planning for delivery in a woman with heart disease is ideally commenced during the antenatal period by the cardio-obstetric team. It should respect maternal preferences after discussion of the risks and benefits of caesarean and vaginal birth, respectively. Vaginal birth with effective neuraxial analgesia is recommended in women with heart disease as it is associated with lower maternal morbidity including haemorrhage, surgical site infection, thromboembolism, and re-exploration. ⁴ No specific maternal benefit was demonstrated in women with heart disease having an elective caesarean birth (without a firm cardiac or obstetric indication) compared to a planned vaginal birth in the study conducted by Ruys et al. ⁶ but adverse fetal outcomes including a higher preterm birth rate and lower fetal birth weight were highlighted in the caesarean cohort.

In some women with heart disease (e.g. fixed CO state, aortopathy, and pulmonary hypertension), active pushing during the second stage of labour is limited or avoided completely. Appropriate analgesia in these cases may permit prolongation of the passive phase of the second stage, allowing further descent of the fetal head and assisted vaginal birth by forceps or ventouse, thus averting maternal expulsive efforts, and blunting the haemodynamic effects of the Valsalva manoeuvre. ⁴

In the Registry of Pregnancy and Cardiac (ROPAC) study investigating outcomes in 5739 pregnancies complicated by cardiac disease, the caesarean birth rate was almost 45% with ∼14% of women presenting for an emergency caesarean. ⁷ Women with mWHO III/IV lesions are more likely to deliver by caesarean birth as are those with high CAPREG II scores. Women may present for caesarean birth due to an obstetric indication, (e.g. abnormal fetal heart rate, breech, and previous caesarean), maternal preference or due to a specific cardiac indication.

The cardiac indications for caesarean birth highlighted in the ESC guidelines include:

1. dilatation of the ascending aorta > 45 mm (> 40 mm for Marfan syndrome, Ehlers-Danlos, or Turner syndrome with an aortic size index > 2.5 cm/m²) or previous aortic dissection,

2. severe aortic stenosis,

3. pre-term labour while on oral anticoagulants (e.g. warfarin)

4. Eisenmenger's syndrome, and

5. severe HF. ⁴

A recent study conducted in Italy by Angeli et al. ⁸ emphasised that adhering to ESC guidelines concerning the mode of delivery for pregnant women with cardiac conditions resulted in improved neonatal outcomes.

Timing of delivery

Timing delivery in a woman with heart disease can be difficult and may be dependent on the cardiac lesion, the cardiac function including echocardiography, obstetric factors, and fetal lung maturity. Preterm birth is not uncommon and was recorded in 16% of women with heart disease in the ROPAC study. ⁷ Low-risk women who are functionally normal could be allowed to go into spontaneous labour. For women with stable heart disease, both the American College of Obstetrics and Gynecology and the ESC guidelines suggest considering elective induction of labour between 39 and 40 weeks gestation if labour does not start spontaneously or if there are no specific indications for preterm delivery. Induction after 37 weeks was associated with lower caesarean birth rates regardless of parity, indication for induction, and cervical favourability. ⁹ Induction in women with heart disease may be performed for cardiac reasons, or obstetric reasons (e.g. maternal or fetal) or geographical reasons.

Induction can be performed using mechanical methods (e.g. Foley's catheter), amniotomy +– oxytocin infusion, dinoprostone (prostaglandin E2 analogue), or misoprostol (prostaglandin E1). ⁴ Misoprostol use is associated with lower cardiovascular side effects. If induction is planned before 34 weeks gestation, antenatal steroids and magnesium sulphate for fetal neuroprotection should be considered. ⁴

Medications prior to labour/birth

Cardiac medications

Pregnant women with heart disease may be on medications that may need to be continued or ceased during the peripartum period. Beta-blockers, calcium channel blockers, alpha agonists, phosphodiesterase-5 inhibitors, diuretics, magnesium sulphate and anti-arrhythmic medications can be safely continued during birth. It may be preferable to keep specific intravenous (i.v.) cardiac medications available in delivery suites/theatres to deal with any specific cardiac emergencies during birth. These need to be specified in the cardiac care plans.

Antiplatelet agents

Aspirin when used for mechanical heart valves (MHVs) should be discontinued for 3 days prior to planned birth whilst for pre-eclampsia, it is common to discontinue aspirin at 36 weeks. Aspirin for ischaemic heart disease (IHD) should be continued during birth, whilst if on clopidogrel, the risk and benefits of its cessation need to be individualised. In women who have had a recent MI, or a coronary stent placed during pregnancy, the benefit of continuing clopidogrel to prevent stent/coronary thrombosis may outweigh the associated risk of bleeding. ¹⁰

Anticoagulants

For pregnant women on anticoagulation for MHV on warfarin (or any vitamin K antagonists [VKA]), the ESC guidelines recommend stopping VKAs at 36 weeks, whereas American College of Cardiology (ACC) guidelines suggest stopping them at least 1 week before the planned birth and transitioning to i.v. unfractionated heparin (UFH) or twice-daily low-molecular-weight heparin (LMWH) regimen.^4,11,12 A peak anti-Xa target of 1.0–1.4 IU/mL, 4 hours following a twice-daily LMWH dose is recommended by the British Society of Haematology (BSH) guideline for monitoring LMWH therapy in women with a MHV, whilst for UFH, an activated partial thromboplastin time (aPTT) of at least twice the normal value is recommended. ¹³ If using LMWH after 36 weeks, both ACC/ESC guidelines advise that LMWH should be replaced by i.v. UFH at least 36 hours before the planned birth, though some maternity units in the UK, continue LMWH and plan its discontinuation depending on the timing of induction and mode of birth.^4,11–13

If a pregnant patient using a VKA presents in labour, the international normalised ratio (INR) should be measured, and consideration should be given to reversing VKA activity (after discussion with the haematology team) with four-factor prothrombin complex concentrate and vitamin K and consider delivery by a caesarean. ¹¹ For women on therapeutic anticoagulation with LMWH, a prophylactic dose of LMWH may be given, or i.v. UFH commenced during induction of labour after discussion with the haematology team. ¹³ If a caesarean is planned, it is recommended to omit the therapeutic dose of LMWH for 24 hours to facilitate neuraxial analgesia/anaesthesia.^12–14 For women on i.v. UFH in labour, it is usually discontinued 4–6 hours prior to birth, which may be difficult to predict and most discontinue it when woman is in early labour. Another option is to use protamine sulphate to reverse UFH, but it has the risk of increasing thrombosis and is reserved for emergencies. ¹²

Labour analgesia

Anaesthetists, as key members of the obstetric cardiac team need to be informed about high-risk women so that they can be assessed and informed about the various analgesic and anaesthetic options during labour or an operative intervention. As the risk of preterm birth is high, women should be referred early and reviewed in the anaesthetic clinic by 28 weeks. Anaesthetic assessment involves reviewing the primary cardiac condition, previous cardiac interventions, presence of other co-morbidities (e.g. diabetes and pre-eclampsia), any cardiac symptoms, cardiac investigations including electrocardiogram (ECG), transthoracic echocardiogram (TTE), cardiac biomarkers (e.g. Troponins or N-terminal pro-brain natriuretic peptide), and cardiac and non-cardiac medications including anticoagulant or antiplatelet agents. In addition, evaluation of the airway, venous access, and examination of the back is undertaken. In some centres, this assessment may be performed jointly in an obstetric cardiac clinic.

Both neuraxial and non-neuraxial analgesic techniques can be utilised during labour in women with heart disease. Neuraxial analgesia techniques that can be utilised include epidural, combined-spinal epidural (CSE) or dural-puncture epidural. The latter technique is not commonly utilised in the UK. Appropriate time intervals need to be followed if the woman is on any antiplatelet or anticoagulant medication prior to performing neuraxial analgesia (Table 2). ¹⁴

Table 2.

Time intervals for antiplatelet agents, anticoagulants, and thrombolytic agents and performance of neuraxial analgesia/anaesthesia (NA). ¹⁴

Antiplatelet/anticoagulant/thrombolytic medications that may be encountered in pregnancy. Antiplatelet agents	Acceptable time interval after medication stopped and performance of neuraxial analgesia/anaesthesia (NA)	Medication administration with a neuraxial catheter in situ	Acceptable time interval to commence medication after performance of NA/catheter removal
Aspirin (< 200 mg/day in women with IHD or pre-eclampsia or a mechanical heart valve)	NA can safely be performed (0 hour)	Can be administered as per routine prescription (0 hour).	Can be administered as per routine prescription (0 hour)
Clopidogrel (75 mg dose)	5–7 days	Not recommended	6 hours
Prasugrel	7 days	Not recommended	6 hours
Ticagrelor	5 days	Not recommended	6 hours
Unfractionated heparin (UFH) Low dose UFH < 100 IU/kg/day s.c OR < 200 IU/kg/day i.v.	4–6 hours Activated partial thromboplastin time (aPTT) should be normal.	1 hour	1 hour
High dose UFH (> 200 IU/kg/day i.v.)	aPTT should be normal	Not usually recommended. If administered for cardiac surgery, follow local guidelines	4 hours but risk-benefit analysis is recommended
Low molecular weight heparin (LMWH) Prophylactic dose	12 hours	Can be administered but caution advised Catheter should only be removed 12 hours after last prophylactic dose	4 hours
Therapeutic dose	24 hours	Not recommended	4 hours if atraumatic NA insertion In presence of traumatic NA, 24–48 hours interval is recommended
Warfarin	International normalised ratio (INR) ≤ 1.4	Not recommended	After catheter removal (0 hours)
Fondaparinux Prophylactic dose (2.5 mg daily dose)	36–48 hours. Anti-Xa levels recommended	Not recommended	6–12 hours
Treatment dose (≥ 5 mg daily dose)	Not recommended. Anti-Xa levels recommended	Not recommended	12 hours
Thrombolytic agents (alteplase, streptokinase. and reteplase)	10 days	Not recommended	10 days

s.c: subcutaneous injection; i.v.: intravenous injection; DOACs: direct-acting oral anticoagulants (e.g. rivaroxaban and edoxaban) are contraindicated in pregnancy.

Epidural analgesia is considered the gold standard for women with heart disease as it provides superior pain relief, blunts the sympathetic changes associated with labour and provides an option to extend epidural analgesia to anaesthesia if the woman proceeds to have a caesarean or an instrumental birth. Studies highlight that effective epidural analgesia during labour is also associated with lower adverse cardiovascular events especially arrhythmia and severe maternal morbidity, especially in high-risk risk women. ¹⁵

Other pharmacological non-neuraxial analgesic techniques include a 50:50 mixture of nitrous oxide: oxygen, and opioids including intramuscular diamorphine/pethidine or i.v. remifentanil patient-controlled analgesia.^12,16 These are often employed when a neuraxial technique cannot be utilised due to anticoagulation or musculoskeletal issues (e.g. scoliosis), when women present in advanced labour or due to maternal preference. Their use is not dependent on the cessation of anticoagulants or antiplatelet agents.

Monitoring during labour or operative delivery

Monitoring during labour should include heart rate, respiratory rate, pulse oximetry, fluid balance and temperature. ⁴ Continuous electrocardiography should be monitored in women at risk of HF, arrhythmia and IHD. High-risk women may benefit from invasive arterial line monitoring that facilitates beat-to-beat monitoring of BP, assessing fluid shifts, and performance of serial blood gases or point-of-care testing.^4,12 During obstetric surgery, monitoring should be in line with the national (Association of Anaesthetists in the UK) recommended guidelines. ¹⁷ Central line use is uncommon, but may be used in HF or for administration of inotropes. ⁴ Pulmonary artery catheters are very rarely used. CO monitoring is uncommon as techniques utilised have not been fully validated in pregnancy. ¹⁸ The use of point of care ultrasound (POCUS) and TTE is growing especially in the setting of peripartum hypotension and pulmonary oedema. ¹⁹ While it is a rapid and non-invasive technique, its implementation may be constrained by the availability of the technology and the presence of trained personnel capable of performing POCUS in the delivery suite. Trans-oesophageal echocardiography may be undertaken in tertiary units in high-risk women having a general anaesthetic (GA) or those with haemodynamic instability. ¹²

Infective endocarditis prophylaxis

Infective endocarditis is rare during pregnancy (0.006%) but when it occurs is associated with high maternal (11%) and fetal mortality (14%). ²⁰ Women with congenital heart disease, MHV, rheumatic heart disease, those with previous history of endocarditis and i.v. drug users are at significant risk. For vaginal birth, routine antibiotic prophylaxis is not recommended in women with heart disease by the ESC guidelines.^4,12 The decision to administer prophylaxis is best individualised based after a discussion with the woman as the benefit of administering them may outweigh the risks of antibiotic resistance or anaphylaxis.

Anaesthesia for caesarean birth (or any operative intervention)

Women may present to the anaesthetist for a caesarean or instrumental birth, manual removal of placenta or a perineal tear or a re-exploration. The options include neuraxial (epidural, single-shot spinal, a spinal catheter, a combined spinal-epidural [CSE]) anaesthesia, or a GA. Factors affecting the utilisation of neuraxial anaesthesia for operative interventions include maternal preference, urgency of delivery, haemodynamic status (e.g. HF), use of anticoagulants or antiplatelet agents (e.g. clopidogrel), and musculoskeletal problems that could make placement of a neuraxial block difficult.

Neuraxial anaesthesia is the preferred technique for most patients in view of it providing superior intra-operative and postoperative analgesia, lower tachyarrhythmia risk, lower blood loss and a better recovery profile. ²¹ Single-shot spinal anaesthesia technique is more commonly utilised for caesarean birth, especially for mWHO I/II lesions. Its performance can lead to a rapid decline in systemic vascular resistance (SVR) that may need to be maintained with vasopressors. The extension of epidural analgesia to anaesthesia, when it's working well during labour for urgent-to-emergency caesarean birth has been described and can be utilised as a de novo technique for high-risk lesions. A CSE technique provides the advantage of consistency of intrathecal local anaesthetic (LA) followed by a more gradual introduction of epidural anaesthesia. It may avoid significant hypotension by decreasing the volume of intrathecal LA and is used for high-risk lesions (mWHO III/IV patients).^21,22

GA can safely be utilised for obstetric (e.g. emergency caesarean and postpartum haemorrhage (PPH)), anaesthetic (e.g. inability to perform neuraxial anaesthesia), cardiac (e.g. HF) indications or maternal preference. For GA, a standard rapid-sequence induction technique with an anaesthetic agent, rapid-onset neuromuscular blocking agent, along with a short-acting opioid (to obtund the pressor response of laryngoscopy, avoid tachycardia, and/or hypertension) is utilised to facilitate tracheal intubation. ⁵ Sugammadex may be preferable to neostigmine for the reversal of neuromuscular blockade induced by rocuronium or vecuronium due to its superior haemodynamic profile. A multi-modal analgesia (using opioids, paracetamol, LA wound infiltration or abdominal wall blocks, and non-steroidal anti-inflammatory agents if not contraindicated) strategy should be utilised during the peri-operative period.

Specific anaesthetic considerations during labour for common cardiac lesions are highlighted in Table 3.

Table 3.

Considerations during labour/delivery in common cardiac conditions. ²¹

Condition	During delivery and immediate postpartum period	Specific goals during labour/delivery
Unrepaired septal defects with left to right shunt (e.g. atrial septal defect, ventricular septal defect, and patent ductus arteriosus)	Increase cardiac output (CO) can lead to heart failure and volume overload. A drop in SVR will promote right to left shunt, decrease oxygenation and cyanosis	Maintain systemic vascular resistance (SVR) Vasopressors (phenylephrine) may be need during neuraxial analgesia /anaesthesia. Consider the use of saline for loss of resistance for epidural Strict fluid balance and avoid fluid overload. Use air filters to prevent air embolism. If pulmonary hypertension present, avoid raised pulmonary vascular resistance (PVR)
Unrepaired septal defects with right to left shunts (e.g. Eisenmenger's syndrome and tetralogy of Fallot)	Increase in CO may promote right to left shunt.	Maintain SVR, arterial line monitoring, and use air filters to prevent embolism. Phenylephrine for a cyanotic spell Decrease PVR, oxygen supplementation as necessary Avoid increasing PVR (hypoxia, hypercarbia, acidosis, hypothermia, nitrous oxide:oxygen analgesia) Avoid carboprost (prostaglandin F2α)
Valvular heart disease Aortic stenosis	Tachycardia will increase oxygen demand and decrease supply. Fixed cardiac output state, risk of heart failure with increase in CO during labour and post-delivery.	Avoid tachycardia, continue beta-blockers, Arterial line monitoring Maintain SVR with phenylephrine. Fluid balance monitoring Effective neuraxial analgesia/anaesthesia Avoid ergometrine and fluid overload
Mitral stenosis	Tachycardia will increase LA overload and cause pulmonary hypertension and arrhythmia risk. Fixed cardiac output state and risk of pulmonary oedema and heart failure increases post-delivery.	Beta-blockade with invasive arterial line monitoring. Avoid hypokalaemia and hypomagnesemia (triggers for atrial fibrillation). Oxygen supplementation if necessary. Effective neuraxial analgesia/anaesthesia. Maintain SVR, avoid tachycardia and treat any arrhythmia immediately. Avoid carboprost (prostaglandin F2α) and ergometrine. Fluid balance monitoring and may need diuretics.
Aortic or mitral regurgitation	Tolerated well. Tachycardia shortens diastole and regurgitant fraction/flow. Pulmonary oedema and heart failure postpartum risk depending on function.	Low SVR tolerated well, avoid hypertension Avoid bradycardia and maintain sinus rhythm Fluid balance monitoring
Prosthetic heart valves	Titrate anti-coagulation as per the haematology care plan. Caesarean birth if woman in labour on warfarin. Titrate APTT if using UFH infusion and stop 4 hours prior to delivery	Increased risk of postpartum haemorrhage. Arterial line monitoring may be considered. Neuraxial analgesia/anaesthesia dependent on anti-coagulation Remifentanil patient-controlled analgesia (PCA) a useful alternative Higher risk of having a general anaesthesia for caesarean Follow national guidelines for postpartum thromboprophylaxis after neuraxial blockade
Aortopathy (Marfan, Loeys-Dietz, and Turner syndrome)	Hypertension and increase in cardiac output increase aortic shear stress and risk of aortic dissection Caesarean birth may have to be considered depending on the aortic diameter.	Avoid hypertension and swings in blood pressure Neuraxial analgesia/anaesthesia preferable Dural ectasia may increase dural puncture risk or contribute to ineffective neuraxial analgesia/anaesthesia. Avoid ergometrine.
Ischaemic heart disease	Tachycardia/hypertension will decrease diastolic time and alter the oxygen supply-demand Increase CO may increase the risk of heart failure	Avoid tachycardia, hypertension, hypotension, and low SVR. Continue beta-blockers, aspirin and individualise clopidogrel therapy. Electrocardiogram (ECG) along with arterial line monitoring during labour. Effective neuraxial analgesia where feasible, remifentanil PCA if clopidogrel continued. Avoid ergometrine and ephedrine as they cause tachycardia.
Arrhythmic condition (Long QT, Brugada, and Pre-pregnancy arrhythmia)	Increased risk of arrhythmia during labour Tachycardia, hyperventilation and electrolyte disturbances increase arrhythmia risk Intracardiac devices may need attention	Keep intracardiac devices switched on. Avoid hypokalaemia/hypomagnesemia ECG monitoring + – arterial line monitoring Avoid tachycardia, continue beta-blockade, effective neuraxial analgesia May need to avoid certain medications that could trigger arrhythmia (websites: Brugadadrugs.org and crediblemeds.org) Cardioversion is safe Ergometrine and ephedrine may need to be avoided
Pulmonary hypertension	The increase in CO may lead to right heart failure	Maintain PVR, continue pulmonary vasodilators, and administer oxygen Arterial line monitoring. Neuraxial analgesia/analgesia preferable. Vasopressin is the preferred vasopressor for severe pulmonary hypertension as it does not affect PVR Avoid ergometrine and carboprost. Diuretics postpartum.

LA: left atrium; LV: left ventricle; APTT: activated partial thromboplastin time.

Location of caesarean birth

Caesarean birth can be performed in obstetric or cardiac theatres (which are reserved for high-risk cardiac lesions). The advantages of performing in cardiac theatre are the availability of a cardiac team, mechanical circulatory support and proximity to a cardiac intensive care unit and conduct of concomitant cardiac surgery. ⁵ Disadvantages include obstetric/neonatal teams working in unfamiliar settings.

Vasopressor and fluid therapy

Vasopressors are utilised to maintain SVR and avoid hypotension, especially in those who receive neuraxial anaesthesia. Phenylephrine (or noradrenaline) is the most employed vasopressor in the UK and can be used in a majority of patients. Ephedrine can cause tachycardia but may be beneficial in a patient with bradyarrhythmia or regurgitant lesions that can tolerate elevated HR; however, its use is associated with a decrease in fetal umbilical artery pH. ⁵ Metaraminol may be preferable in patients with long QT syndrome.

During labour, women are allowed to drink clear fluids whilst those having an epidural are administered i.v. balanced crystalloid solution to prevent dehydration and acidosis. Accurate fluid balance monitoring is critical in all cardiac lesions. Specific filters that trap air may be useful, especially in atrial/ventricular septal defects to prevent air embolism. In specific lesions such as Fontan or hypertrophic cardiomyopathy, intravenous fluids should be administered post-anaesthesia, to maintain adequate preload and intravascular volume during operative delivery. High-risk women are at significant risk of pulmonary oedema and HF following delivery and the team should be prepared to deal with these emergencies during the intrapartum period.

Intracardiac devices

Any intracardiac device in a pregnant woman (pacemaker and intra-cardiac defibrillator) should be checked for its indication, type, its functioning, location, and battery health antenatally.^12,23 A magnet and a defibrillator should always be available in the delivery suite.

Intracardiac devices should be kept on during labour and caesarean birth. An infra-umbilical incision is unlikely to cause electromechanical interference (EMI). For patients with abdominal generator placement, it may be necessary to reprogram the device during the caesarean. This can be done via planned re-programming or placing a magnet to prevent EMI during surgery. For any devices that have been de-activated, the patient should have ECG, pulse oximetry and BP monitoring with defibrillation pads in place. The cardio-obstetric team should ensure that the device if switched off during the intrapartum period, is switched back on and working appropriately prior to discharging patients from the hospital.

Uterotonics

Oxytocin remains the first line uterotonic agent but needs to be administered by a slow infusion as a bolus can cause significant hypotension due to a decline in SVR. Ergot alkaloids (ergometrine or methylergometrine) can also be used, but they are usually avoided in hypertensive disorders of pregnancy, aortopathy, significant tachyarrhythmias, ischaemic and severely stenotic valvular heart disease. Their use is associated with coronary vasospasm and coronary ischaemia, especially in the setting of anaemia, haemorrhage, and intravascular depletion. ⁴ Prostaglandin F2α (carboprost) can be used in the absence of severe asthma and pulmonary hypertension. It can raise PVR significantly and hence is also avoided in severe stenotic and regurgitant left heart valvular lesions that are associated with raised pulmonary artery pressures. Misoprostol is weak uterotonic and can be used in most patients. There are case reports of the use of carbetocin in heart disease in pregnancy and more research is needed regarding its safety in cardiac disease. ²⁴

Postpartum haemorrhage

PPH is commonly observed in pregnant women with specific congenital heart defects (e.g. Fontan) and those with MHV. Emergency caesarean birth, use of LMWH during pregnancy, use of general anaesthesia and higher CARPREG score were associated with PPH. The usual pharmacological and non-pharmacological interventions (e.g. bimanual compression Bakri balloon, B-Lynch suture, etc.) should be utilised to manage PPH. Point-of-care testing (e.g. thromboelastometry) should guide blood product usage. Tranexamic acid use, irrespective of dosing was not associated with increased risk of thrombo-embolic events in a meta-analysis of 216 studies and can be used in women with IHD and MHV's.^10,25

Postpartum care

Post-delivery, women with cardiac disease may need monitoring in an obstetric high-dependency unit or a critical care unit depending on the cardiac lesion and/or any obstetric or cardiac morbidity experienced during birth. Management should focus on optimising BP, thromboprophylaxis, multimodal analgesia, and postoperative investigations including monitoring for HF, arrhythmias, or dissection. A transthoracic echocardiogram may be necessary in certain high-risk women following delivery.

In those with MHV, UFH may be commenced 4-6 hours after delivery and its dosing titrated as per aPTT. Alternatively, a prophylactic dose of LMWH may be administered 4 hours after the performance of neuraxial block or removal of epidural catheter. Therapeutic doses of LMWH are usually delayed for 24–48 hours after delivery. ¹³ The patient can be transitioned to warfarin within 5–7 days of delivery. Breast feeding is safe in the presence of anticoagulants. Appropriate contraception (usually progestin-based or intra-uterine devices) with low thrombogenic risk should be given. The cardio-obstetrics team should continue to review the parturient postpartum in a dedicated outpatient follow-up clinic.^3,4

It is essential to include pertinent information regarding the cardiac condition, intrapartum care, and the medications women are undertaking in the hospital discharge summary. This information should be communicated to both the community midwifery team and the general practitioner to ensure continuity of care and postpartum surveillance following discharge. Women should also be educated to comply with their cardiac medications, whilst those with specific lesions (e.g. Marfan or those with aortopathy) should be informed about specific red flag symptoms (e.g. chest pain, back pain, and collapse) of aortic dissection and whom to contact if they develop them.

Special circumstances

Arrhythmia

Supraventricular tachyarrhythmia (SVT) and atrial fibrillation (AF) remain the most common arrhythmias reported in literature during pregnancy. For unstable arrhythmia, (HF, MI, syncope, and shock), cardioversion undertaken with sedation, or a GA is recommended. ²⁶ An anterior-posterior position for defibrillation pads is recommended.

For stable tachyarrhythmia, fluid resuscitation, electrolyte correction, performance of 12-lead ECG, blood gas and X-ray chest should be considered and managed in line with resuscitation guidelines. Therapeutic anticoagulation may be necessary in patients in whom the duration of AF is > 36–48 hours. ⁴ Immediate cardioversion is recommended for both haemodynamically stable and unstable ventricular tachycardia. ⁴ Amiodarone can be used if other medications fail, but its disadvantages include neonatal hypothyroidism and neurodevelopment sequalae.

Heart failure

This is the second most common complication seen intrapartum with one study suggesting 27% of all HF events observed in pregnancy occur during delivery. ²⁷ Acute management consists of optimising oxygenation, treatment with diuretics, vasodilators along with inotropes as necessary. For antepartum women, hospitalisation, beta-blockers, optimising BP, and delivery planning by the cardio-obstetric team (based on fetal maturity) are commonly undertaken. For postpartum women with severe peripartum cardiomyopathy, BOARD regimen – Bromocriptine, Oral HF medications (beta-blockers, ACE-inhibitors, mineral receptor antagonists), Anticoagulation, vasoRelaxing agents if BP > 110 systolic and Diuretics may be introduced with non-invasive ventilation if necessary. ⁴

Pulmonary hypertension

Pulmonary arterial hypertension (PAH) from any cause is classed as a mWHO IV lesion by the ESC guidelines suggesting pregnancy should be avoided. ⁴ Though it's rare, it is one of the cardiac lesions that is associated with the highest maternal morbidity (50%–70%) and mortality varying between 10% and 33%.^28,29 Women may present for termination hence these patients need to be discussed early by the pregnancy heart team involving specialists including critical care, cardio-thoracic team as well as those that can facilitate extracorporeal membrane oxygenation (ECMO) in cases of severe PAH. Termination is best performed medically with mifepristone. ³⁰ Sildenafil, an oral selective phosphodiesterase 5 inhibitor, is recommended as the first-line agent and is safe from breast feeding point of view. Prostacyclin analogues administered parenterally (epoprostenol), inhaled (iloprost) or via subcutaneous (treprostinil) routes that target the PGI₂ pathway are other agents commonly utilised. Pulmonary vasodilators that are also useful include nitric oxide, supplementary oxygen and diuretics that also maintain fluid balance/euvolaemia in these cohorts. Anticoagulation may be necessary in either prophylactic or therapeutic doses and must be individualised. Delivery if pregnancy is continued is often preterm and should be carried out in a tertiary or a specialised regional centre. Though caesarean birth performed preferably with a neuraxial anaesthetic is recommended for those with severe PAH, vaginal birth utilising epidural analgesia technique may be feasible and safe with one study reporting no maternal mortality when women with mild-to-moderate PAH delivered vaginally. ²⁹ Patients often are admitted to critical care postpartum and ECMO may be necessary in those with severe right ventricular dysfunction. HF, arrhythmia, thrombo-embolism, and PPH are common and contribute to severe maternal morbidity.

Mechanical circulatory support

This can only be provided in specialised centres. Options include extracorporeal membrane oxygenation (ECMO), intra-aortic balloon pump and ventricular assist devices. These may be utilised for peripartum cardiogenic shock, HF refractory to medical management, in cardiac arrest, or as a bridge to further therapy or heart transplant. ³¹

Aortic dissection

This is an emergency (0.5–1.1 per 100,000) usually seen in the third trimester or postpartum and swift recognition is essential as intervention from the obstetric, anaesthetic, vascular, critical care, and/or cardiothoracic surgical teams may be necessary. ³² Patients classically complain of acute sudden onset back pain, have a neurological deficit, or experience haemodynamic collapse. A CT scan imaging the entire aorta is diagnostic. Management consists of treating pain, maintaining normotension to avoid extending dissection and good fluid resuscitation with invasive monitoring. For Type A dissection, aortic surgery with cardio-pulmonary bypass is necessary. For type B dissection, endovascular repair is usually preferable.

Cardiac arrest

Though rare (0.4% in 1938 women in the CARPREG II study), maternity teams should be prepared to deal with maternal collapse. ¹ Obstetric cardiac arrest team needs to be summoned as quickly as possible. One member of the team should be assigned the task of recording interventions. It is essential to obtain i.v. access above the diaphragm or consider intra-osseous access (humerus). Advanced airway management using endotracheal intubation is advisable. Standard life support algorithms, medications and defibrillation energies should be utilised as for non-pregnant patients. If ≥ 20 weeks gestation, manual displacement of the uterus should be performed and if there is no return of spontaneous circulation within 4 minutes of standard resuscitation, a resuscitative hysterotomy (peri-mortem caesarean) should be performed. Extracorporeal cardiopulmonary resuscitation can be considered but may be limited by its availability in specialised centres. ³³

Conclusion

Multidisciplinary care led by the cardio-obstetric team is essential for the safe peripartum management of pregnant women with heart disease. Optimising cardiovascular health before and during pregnancy, along with individualised care plans based on risk stratification, allows for safe delivery in an appropriate setting with tailored hemodynamic monitoring, analgesia, and anaesthesia. Preparedness for both obstetric and cardiac emergencies, along with a thorough postpartum follow-up by the multidisciplinary team, are critical components, for effective management of cardiac disease during childbirth.