Is Pregnancy Safe for the Woman with Complex Congenital Heart Disease? Making Progress Creating a Rational Approach

Advances in surgery and intervention for congenital heart disease (CHD) have resulted in a survival estimated at 85-90%, thereby creating an expanding population of adults.¹ The most recent statistics from the American Heart Association estimate 1 in 150 adults have some form of CHD. The number of adults with CHD has surpassed the number of children--estimated at 1,400,000 adults compared to 1,000,000 children in 2010 in the United States.² Nearly one-third of these patients have severe CHD. Therefore, there is an increasing number of women with complex CHD of childbearing age who would like to consider pregnancy. In the past, pregnancy in these women was dismissed as “too dangerous” to consider. Despite warnings from clinicians, women with a repaired complex CHD have presented during pregnancy and provide the basis of recommendations for their care. The literature is replete with case reports and expanded case reports chronicling their course and complications. This has evolved into registries such as ROPAC³ and ZAHARA⁴ , as well as risk assessment tools from the CARPREG study⁵ and World Health Organization classification of risk.⁶ These provide important information about the risks of pregnancy in women with all forms of CHD. The challenge in the care of the adult survivors with CHD is their uniqueness with respect to their post-surgical anatomy, natural/unnatural history and clinical status. Extrapolating from large studies when different types of congenital lesions are included can be a problematic feature of this literature. Pregnancy is a time of hemodynamic turbulence. The expected increase in preload or decrease in afterload could potentially be deleterious to certain cardiac lesions. Women become increasingly hypercoaguable. These changes progress during the course of pregnancy and must be considered in the management of women with complex CHD. Potential cardiac complications at different gestational stages should be anticipated. For example, the expected increase in stroke volume and cardiac output may impact significantly on the patient with a systemic right ventricle.^7,8 Severe systemic ventricular dysfunction and pulmonary hypertension have in the past and remain the most dangerous underlying limitations to an uncomplicated pregnancy and are associated with increased maternal morbidity and mortality.⁹ Although there is improved survival in the CHD population, maternal mortality from cardiac disease has not changed and remains a problem in the developed world.¹⁰

The Canobbio scientific statement on management of pregnancy patients with complex congenital heart disease is an important and timely summary of clinical issues.¹¹ This paper discusses the cardiac physiology of pregnancy related to expected complications in women with heart disease, specifically repaired complex CHD. Based upon a growing body of literature, risk assessment, complications and management strategies are outlined. Preconception evaluation and evaluation during pregnancy is highlighted with respect to important caveats in the women with repaired, complex congenital heart disease. General management issues are described and specific high risk lesions are addressed in detail including: pulmonary hypertension, aortic stenosis and left ventricular outflow obstruction, D-transposition of the great arteries, and the single ventricle/Fontan circulation. This statement emphasizes the major problems and controversies in the care of these women.

Scientifically robust data regarding the care of adults with CHD is increasing. However, because controlled randomized trials are not performed during pregnancy, most of the information is gleaned from case reports or expanded case reports. Often this information does not come from specialized centers and survey general practice patterns and observations.1 Guidelines are available based on the existing data but often extrapolate to the pregnancy state.^3,4,12,13 Often in the publications, the complex lesions are lumped together making it difficult to generalize to a specific diagnosis. Particularly, the pregnancy risk assessment studies and classifications may include various cardiac pathologies and types of repair. As the registries such as ROPAC³ and ZAHARA⁴ expand, more lesion/repair specific information will be available. Also large cohorts with long-term follow up of more standardized care will require multicenter cooperation and help in the future formulation of lesion/repair specific recommendations.

One of the class I recommendations throughout the ACC/AHA guidelines was the need for preconception consultation in this population in the population of in women with complex CHD.¹² This is imperative to assess the feasibility of pregnancy with the additional volume load, tachycardia and hypercoagulable state balanced with the need for diagnostic testing and continuing medication during pregnancy. This is imperative in this patient population and must be communicated to general cardiologists as well as obstetricians. Most of the information obtained about cardiac complications of pregnancy is based upon problems occurring during the course of pregnancy. There is no clinical data to demonstrate the impact of preconception evaluation; however, this process can identify women who may require another surgery or intervention to improve their overall clinical status making them a better candidate for a safe pregnancy. For example, the woman with a pacemaker or AICD would best be evaluated prior to pregnancy for device efficacy and generator longevity to avoid replacing the device during pregnancy. This is a time to discuss not only potential risks of pregnancy but the impact pregnancy may have on cardiac function in the future. It is also an opportunity to discuss and prescribe appropriate birth control.

The management of pregnancy in women with complex CHD requires a careful, rational approach considering both the safety of medications and interventions as well as efficacy and necessity of treatment.^7,8 The risks of complications are discussed in the statement as a part of preconception counseling and during the course of her pregnancy.¹¹ Guidelines are available for the judicious use of medications during pregnancy which need to be continued to maintain a health of the mother.^7,8,11,13 An algorithm for preconception evaluation and pregnancy management is illustrated in the statement which is a useful guide.¹¹

The postpartum period can be hemodynamically critical for the woman with CHD as she redistributes the excessive volume load of pregnancy and especially for the systemic right ventricle for example. Although the first 24-48 hours are critical, these hemodynamic alterations may persist for up to six months postpartum.

The scientific statement highlights the need for expertise in cardiology and obstetrics in the care of these patients at a specialized center.^10,11 Pulmonary hypertension, systemic ventricular dysfunction or prosthetic valve management require very close, often multispecialty and highly specialized care. This expertise must begin with the transition phase of care to an adult facility and reproductive issues should be discussed at menarche. Currently, young women may be lost to follow up after leaving pediatric care and only return when pregnant.¹⁰ The importance of a specialized center is emphasized for the management patient s with complex CHD as well as during a potentially high risk pregnancy. This specialized clinical center must provide training in cardiology, obstetrics and anesthesiology.

In conclusion, there are three important clinical issues in the care of women with complex CHD: preconception evaluation and intervention; management strategies during pregnancy, including diagnostic testing and medications; and, the need for specialized centers to facilitate transition from the pediatric care and understand the complexities of CHD in the setting of pregnancy. These clinical guidelines are often based on essentially expert opinion which highlights the need for future research.¹ This scientific statement illustrates the need to develop large cohorts of patients to assess the outcome preconception intervention and the incidence of pregnancy complications as related to specific congenital lesions.11 These future studies will require multicenter collaboration and standardization of management to best assess pregnancy outcome and, ultimately , the impact upon maternal cardiac mortality. This is a call to action: to implement practice guidelines and then asses the results of this rational approach in very complex and potentially complicated population of women.