Early in the first trimester, women with CHD should meet their obstetrician and cardiologist for a review of their clinical status, to discuss the schedule of antenatal care, and the timing and mode of delivery. Women should be made aware that delivery within a hospital setting is recommended, on a consultant-led delivery suite/labour ward, regardless of their underlying lesion. Although the exact level of care required will be decided later in pregnancy for those individuals who are assessed as having low-risk lesions (such as small left to right shunts or valvular regurgitation with normal ventricular function), it may be appropriate to receive their obstetric care in a local obstetric unit rather than in a specialist centre. Local care can be enhanced by a comprehensive cardiac assessment at PCC or early in the first trimester, so that any pertinent issues can be clarified and further investigations and follow-up arranged. If the local obstetric unit feels unable to care for these patients, then their care should be transferred to specialist centres, which routinely manage women with CHD.

Every woman with CHD should have a detailed delivery plan completed in the third trimester. This delivery plan should follow from a joint co-ordinated assessment by the obstetricians, cardiologists and anaesthetists. Within this plan there should be clear written information regarding the proposed place of delivery; mode of delivery; the type of monitoring the patient needs to receive, which members of the medical team need to be informed should any problems arise; the recommended pain relief required; and the specific management of the second and third stage of labour and postdelivery monitoring.

Rates of Caesarean section are much higher in women with CHD [6], reflecting the desire to avoid an emergency Caesarean section in this group of patients. To date, advice regarding the mode of delivery in women with congenital heart disease (CHD) has been based exclusively on expert opinion with little or no data to guide clinicians. The recent paper based on the ROPAC dataset from over 1,200 deliveries showed that a planned Caesarean section did not confer any maternal advantage when compared with attempted vaginal delivery [7]. In fact, comparing planned vaginal delivery with planned Caesarean section showed that babies were delivered earlier and were consequently of a lower birthweight, whilst maternal outcomes were worse with higher maternal mortality and rates of heart failure. This could reflect the fact that planned Caesareans were more common in women with worse heart disease, but even when this was corrected for, the differences remained, with higher rates of heart failure, lower birthweight and shorter gestation, suggesting that elective CS was associated with no maternal benefit and a worse fetal outcome. Most importantly, from a maternal point of view, the outcome of emergency CS performed in labour was no worse than for those having a pre-labour elective CS. These data suggest that vaginal delivery can be attempted in most women, with CS reserved for those with an obstetric indication. The ESC guidelines suggest that women on oral anticoagulation in preterm labour and patients with Marfan syndrome and an aortic diameter of greater than 45 mm should be delivered by CS [8]. The current data suggest that attempted vaginal delivery is safe in all others and that emergency CS carries no greater risk than elective CS. More research, focussed on the outcome of labour in women with severe heart disease, needs to be performed.

A spontaneous onset of labour followed by a vaginal delivery is the best option for women with CHD and, in the absence of obstetric factors (preterm ruptured membranes, fetal growth restriction, pre-eclampsia); there are no data to support early induction of labour. However, in the noncardiac population, induction of labour in many groups has been shown to be safe and does not increase the rate of Caesarean section before 40 weeks of gestation and to actually reduce CS rates after 40 weeks [9, 10]. Perhaps more importantly, induction at 40 weeks reduces stillbirth rates by around 50 % [11]. Consequently, in women with CHD who experience higher rates of stillbirth, a policy to induce labour at 40 weeks may be beneficial and consistent with improving pregnancy outcomes but currently has no evidence base. Should induction of labour be required, then artificial rupture of membranes and oxytocin infusion are preferred. If prostaglandins are required to promote cervical ripening, caution should be used as there is the risk of uterine hyperstimulation, which may then require emergency delivery. It may be preferable to consider mechanical methods of cervical ripening such as a Foley catheter or cervical laminaria.

During labour in normal (noncardiac patients) women, cardiac output progressively increases to reach a maximum in the second stage [12]. There are no equivalent data in women with heart disease, and the data from Robson et al. are taken from women without epidural anaesthesia and may therefore be a response to pain. Current recommendations are for women with CHD to have an early epidural to minimise pain and so the increase in cardiac output, but there are no data to support this. In the non-pregnant state, adverse cardiac events are infrequently associated with exercise. However, these data are on the background of a normal cardiac workload, which is not the case in pregnancy where the cardiac output is increased by up to 50 % from non-pregnant levels.

At the onset of the second stage, passive descent of the fetal head is permitted. For women with an epidural, this increases the chance of a spontaneous vaginal birth, reduces the overall time required for pushing and reduces the likelihood of an assisted delivery [13]. An active second stage is considered to be appropriate for the majority of women with CHD. Prior studies demonstrated a preference to replace the active second stage with an immediate assisted delivery [14]. However, this is currently only routinely recommended for patients with a dilated aorta [8]. More recent data demonstrate that despite an active second stage, women with CHD are still more likely to have an assisted vaginal delivery because of an imposed shortened stage [14]. At present there are no studies examining how the active second stage should be managed in this group and whether a shortened second stage is beneficial. Information regarding the recommended length of an active second stage should be clearly documented in the patient’s labour plan.

Present guidance recommends that women without heart disease may opt for a physiological third stage if the risk of post-partum haemorrhage is deemed to be low [15]. However, women with cardiac disease have a reported greater risk of post-partum haemorrhage, which may complicated up to a quarter of deliveries, and so an “active” third stage of labour is recommended [16]. Obstetric haemorrhage should be avoided in this group because of the large associated fluid shifts at delivery, which may be poorly tolerated in the parturient with cardiac disease. Oxytocin is widely used to counter uterine atony, as first-line uterotonic agent for the active management of the third stage of labour, as it shortens the length of the third stage and reduces blood loss and the rate of post-partum haemorrhage [17]. A UK postal survey of obstetricians and midwives found that Syntometrine was the most commonly used agent for the active management of the third stage of labour [18]. However, the use of ergometrine in women with cardiac disease is not advised because of its marked hypertensive effect [19] and association with coronary artery spam and myocardial ischaemia [20]. Furthermore, oxytocin is not without its own side effects, most notably, vasodilatation of the subcutaneous vessels combined with vasoconstriction in the splanchnic bed and coronary arteries as well as an effect on cardiac receptors to increase heart rate [21], the overall effect being a tachycardia and hypotension. These effects are dose related so the minimum effective dose of oxytocin is suggested. At present no studies have directly evaluated different oxytocin regimens for the management of the third stage with reduced rates of haemorrhage as a primary endpoint. Should second- or third-line agents be required, misoprostol and Hemabate can be utilised for the treatment of post-partum haemorrhage, but the former is associated with pyrexia and the latter with marked gastrointestinal upset.

During labour, women should have both continuous fetal monitoring (CFM) and maternal cardiac monitoring. Basic non-invasive monitoring should include an ECG for the detection of maternal arrhythmia in labour. A 12-lead ECG can be performed in the event of signs or symptoms of ischaemia. There are clear limitations of basic non-invasive monitoring, and so regular medical review by an appropriately experienced doctor monitoring is necessary. For women with high-risk cardiac lesions, invasive cardiovascular may be prudent, usually in the form of an arterial and of uncertain benefit line and occasionally a central venous line. A Swan-Ganz catheter is rarely indicated. The need for these additional forms of monitoring should be included in the antenatal delivery plan.

Anaesthetic involvement in the antenatal care of women with cardiac disease is essential. Anaesthetists must be part of the team who assess these patients and monitor them through their pregnancy. In more complex cases, anaesthetists will need time to understand the patient’s cardiovascular physiology and how labour, anaesthetic and obstetric interventions might affect it. Plans for the timing and mode of delivery, and how best to provide analgesia or anaesthesia for this, should be made by a multidisciplinary team of anaesthetists, obstetricians and cardiologists. Even if vaginal delivery is planned, emergency operative delivery may be indicated for obstetric reasons, so an anaesthetic plan must be made for both the expected mode of delivery and emergency intervention. The vast majority of women with cardiac disease will have an anaesthetic intervention, either in the form of regional analgesia for labour or anaesthesia for operative delivery.