PH is defined as a mean pulmonary arterial pressure (PAP) ≥25 mm Hg at rest, diagnosed by right heart catheterization. PH is classified into five broad categories: idiopathic pulmonary arterial hypertension (PAH, WHO Group I); PH due to left heart disease (WHO Group II); PH due to lung disease (WHO Group III); PH due to thromboembolic disease (WHO Group IV); and PH due to unclear or multifactorial etiologies (WHO Group V). PAH carries a high mortality risk during pregnancy, although this risk is decreasing,34
because the pulmonary circulation is not able to adapt to increased cardiac output seen in pregnancy, leading to further increased PAP and RV failure.34
PH is further exacerbated by the prothrombotic state of pregnancy. Maternal mortality is more favorable in women with idiopathic PAH with recent reports of mortality of 17%, decreased to 9% with therapy, and is associated with RV systolic function.1,34,35
Regardless of the etiology, PH carries a guarded prognosis during pregnancy, although the greatest risk may be seen in women with Eisenmenger syndrome.36,37
Eisenmenger syndrome develops when, in the presence of left-to-right shunt, progressive PH leads to shunt reversal or bidirectional shunting as a result of chronically increased pulmonary vascular blood flow with accompanying pulmonary vascular resistance exceeding systemic vascular resistance. Although this syndrome may rarely occur with ASD, VSD, or PDA, the low-pressure/high-flow shunt seen in ASD is far less likely to result in PH and shunt reversal than is the condition of high-pressure/high-flow symptoms seen with VSD and PDA.
In Eisenmenger syndrome, during the antepartum period, decreased systemic vascular resistance in the setting of fixed, high pulmonary resistance increases both the likelihood and the degree of right-to-left shunting. Pulmonary perfusion decreases, with systemic hypotension resulting in hypoxemia with subsequent maternal, then fetal deterioration. The peripartum development of systemic hypotension leads to decreased RV filling pressures; in the concomitant presence of a fixed cardiac output state (eg, PH), such decreased right heart pressures may be insufficient to perfuse the pulmonary arterial bed, leading to a sudden and profound hypoxemia and death.
Maternal mortality in the presence of Eisenmenger syndrome is approximately 28% and has been reported to decrease to 23% with use of targeted therapies for PH.34,38,39
Eisenmenger syndrome associated with VSDs appears to carry a higher mortality risk than that associated with PDA or ASDs. In addition to the previously discussed problems associated with hemorrhage and hypovolemia, thromboembolic phenomena have been associated with up to 43% of all maternal deaths in Eisenmenger syndrome.37
Sudden delayed postpartum death, occurring 4 to 6 weeks after delivery, has also been reported.37,40
Such deaths may involve a
rebound worsening of PH associated with the loss of pregnancy-associated hormones, causing RV failure, arrhythmias, or thromboembolic events.
Management of PH and Eisenmenger Syndrome in Pregnancy
Recent studies suggest that maternal mortality may be lower in patients with mild PH, lower NYHA class, and PH from left HF.41,42
However, the identification of women at lower risk remains a challenge. Thus, the current American College of Cardiology (ACC) and European Society of Cardiology (ESC) guidelines advise against pregnancy in women with PAH and recommend termination for those who become pregnant due to the high mortality associated with continuing pregnancy (WHO risk class IV).3,35
For patients choosing to continue gestation, management centers on decreasing pulmonary vascular resistance, maintaining RV preload, LV afterload, and RV contractility. Thus, factors that increase pulmonary vascular resistance ought to be avoided, and patients should be routinely monitored for occurrence of symptoms, signs of HF, worsening RV function, and increased levels of brain natriuretic peptide. In general, sympathetic agonists (epinephrine and norepinephrine) and conditions resulting in hypoxia or hypercarbia are associated with a poor outcome. Thus, the mainstays of therapy and management for hypoxia continue to be inpatient care in a tertiary care center with experienced clinicians, with continuous administration of oxygen, use of pulmonary vasodilators, avoidance of hypotension and anemia, judicious diuretic use as necessary, and limited use of operative deliveries requiring general anesthesia, as these have been associated with worse outcomes.39,43,44
Inhaled nitric oxide has been used to decrease pulmonary vascular resistance and improved pulmonary blood flow and oxygenation, in conjunction with supplemental oxygen.35
Anticoagulation for Eisenmenger syndrome in pregnancy outside of the usual indications is controversial and not supported by large trials. Evidence suggests early planned delivery around 32 to 34 weeks for women with moderate to severe PH and 35 to 37 weeks for women with mild PH may be reasonable.34,41,42,45
Prophylaxis for endocarditis with antibiotics should be considered as described in Table 28.3
Given the elevated mortality risk postpartum, immediately postdelivery patients should be monitored in an intensive care setting, where careful monitoring of hemodynamics can take place.35
Additionally, current recommendations include at least 1 week of in-hospital monitoring for RV failure and PH medication titration.35
Table 28.3 Antibiotic Prophylaxis for Cardiac Lesions With Highest Risk of Bacterial Endocarditis
Prosthetic cardiac valves or prosthetic material used for cardiac valve repair
Previous infective endocarditis
Unrepaired cyanotic heart disease, including palliative shunts and conduits
Completely repaired CHD using prosthetic material or device, whether replaced by surgery or by transcatheter intervention, during the first 6 mo after procedure
Repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or device
Patients who underwent cardiac transplantation with valvular regurgitation due to a structurally abnormal valve
CHD, congenital heart disease.
These recommendations are based on American College of Cardiology/American Heart Association guidelines, which specifically discourage endocarditis prophylaxis for “routine” vaginal or cesarean delivery. Specifically, the guidelines comment on prophylaxis as reasonable for patients at the highest risk of adverse outcomes from infective endocarditis, as listed above. Given a possible increased risk of endocarditis with complicated deliveries such as retained placenta, alongside recommendations to give antibiotics before or within 30 minutes of starting a “complicated” procedure, the decision to hold or administer bacterial endocarditis prophylaxis is not necessarily straightforward.22 Thus, many obstetricians may elect to administer prophylactic antibiotics to cover unpredictable complicated deliveries.
Adapted from Nishimura RA, Otto CM, Bonow RO, et al. 2017 AHA/ACC focused update of the 2014 AHA/ACC Guideline for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2017;135(25):e1159-e1195.
Invasive monitoring with an arterial line and central venous catheter is indicated for close monitoring for hypotension and volume status of the decompensating patient. A pulmonary artery catheter will provide useful information among some patients with moderate to severe PH from interatrial shunts.6,44,47
Reference values are provided in Table 28.4
. However, among patients with interventricular shunts, catheter placement is associated with a
high rate of complications, including arrhythmias, embolization, and pulmonary artery rupture.34
In instances in which pulmonary artery catheterization may be of benefit, simultaneous cardiovascular imaging may be helpful in catheter placement. If the possibility of right-to-left shunting exists, balloon inflation with carbon dioxide is preferable to that with air in an effort to avoid systemic air embolus associated with the rare occurrence of balloon rupture.
Table 28.4 Reference Values With Central Hemodynamic Assessment
Cardiac output (L/min)
Heart rate (bpm)
Pulmonary vascular resistance (dyne/cm/s5)
Systemic vascular resistance (dyne/cm/s5)
Mean arterial pressure (mm Hg)
Pulmonary capillary wedge pressure (mm Hg)
Central venous pressure (mm Hg)
Bpm, beats per minute. Values are derived from 10 selected patients at 36 to 38 week gestation and again at 11 to 13 week postpartum with arterial lines and Swan-Ganz catheters to characterize central hemodynamic values of pregnancy.
From Clark SL, Cotton DB, Lee W, et al. Central hemodynamic assessment of normal term pregnancy. Am J Obstet Gynecol. 1989;161(6):1439-1442.
In consideration of catheter placement, it is of note that, during labor, uterine contractions are associated with a decrease in the ratio of pulmonary to systemic blood flow.48,49
Pulmonary artery catheterization and serial arterial blood gas determinations thus theoretically allow the clinician to detect and treat early changes in cardiac output, pulmonary artery pressure, and shunt fraction. Because the primary concern in such patients is the avoidance of hypotension, any attempt at preload reduction (ie, diuresis) must be undertaken with caution, even in the face of initial fluid overload. Some clinicians prefer to manage such patients on the “wet” side (wedge pressure range of 16-18 mm Hg), maintaining a preload margin of safety against unexpected blood loss with an a priori acknowledged risk of pulmonary edema. Because of the increased risk of significant blood loss and hypotension associated with operative delivery, cesarean delivery should be reserved for standard obstetric indications, although many patients have elected to schedule cesarean deliveries in an attempt to avoid overt hemodynamic fluctuations.35
Similarly, midforceps delivery is not warranted to shorten the second stage but should be reserved for obstetric indications only. Likewise, large volume boluses should be avoided, as these can alter the peripartum hemodynamics.
The issue of pulmonary artery catheterization is controversial in Eisenmenger and specifically advised against in patients with this disorder the most recent ACC Scientific Statement.35
If operative delivery is necessary, meticulous attention to hemostasis and surgical technique with an experienced surgical team minimizes the risk of blood loss, hypotension, and death in these patients. Despite expert management, a substantial risk of maternal mortality remains during labor and delivery. Laparoscopic tubal ligation under local anesthesia has also been described in a group of women with various types of cyanotic cardiac disease.50
Anesthesia for patients with PH is controversial. Theoretically, general and single-dose spinal anesthesia, with its accompanying risk of hypotension, should be avoided. Regional techniques for both vaginal (epidural) and cesarean (spinal) delivery have been described and successfully used.34,51
Although any number of inciting events resulting in systemic hypotension in pregnancy may exist, Eisenmenger syndrome most frequently results from hemorrhage or complications of spinal anesthesia.38
Thus, avoidance of systemic hypotension is the principal clinical concern in the intrapartum management of patients with PH of any etiology. This fact is underscored by the longstanding knowledge that the greatest maternal risk occurs in the peripartum period, and most deaths occur between 2 and 9 days’ postpartum.34
The precise pathophysiology of such decompensation is unclear, and it is uncertain what, if any, therapeutic maneuvers prevent or ameliorate such deterioration.