Chapter 33: Cardiovascular Disease in Pregnancy

Introduction

General Considerations

Cardiovascular disease occurs in up to 4% of pregnancies, but the incidence is increasing due to improved prognosis of women with congenital heart disease and a trend toward older maternal age. The unique hemodynamic changes associated with pregnancy make diagnosis and management of heart disease in pregnant patients a challenge to the physicians, who must consider not only the patient but also the risks to the fetus.

In general, the normal hemodynamic changes associated with pregnancy are well tolerated by those who have a normal cardiovascular system, valvular regurgitation, and left-to-right intracardiac shunts. On the other hand, the highest maternal and fetal morbidity and mortality is seen with severe obstructive valvular lesions, severe aortic disease (dilated thoracic aorta or uncorrected coarctation), New York Heart Association (NYHA) class III or IV heart failure, uncontrolled hypertension, and cyanotic congenital heart disease. As a rule, spontaneous vaginal delivery, often with use of vacuum extraction or forceps to facilitate stage 2 of labor to avoid the hemodynamic stress associated with pushing, is preferred. Cesarean section, with few exceptions, should be reserved for obstetric indications.

Cardiovascular Physiology of Normal Pregnancy

Normal pregnancy is accompanied by significant physiologic changes, although the specific mechanisms remain virtually unknown (Table 33–1). This increased hemodynamic burden of pregnancy may unmask previously unrecognized heart disease. The normal signs and symptoms associated with pregnancy, such as shortness of breath, fatigue, and exercise intolerance, may obscure the diagnosis of heart disease. The clinician must, therefore, have a thorough knowledge of these normal changes and the aspects of the history and physical examination that suggest the presence of heart disease.