Cardiovascular Complications of Pregnancy

Introduction

Pregnancy-related hypertension (eclampsia and preeclampsia) is discussed in Pregnancy Section.
Cardiomyopathy of Pregnancy (Peripartum Cardiomyopathy)
In approximately one of 4000-15,000 patients, dilated cardiomyopathy develops in the final month of pregnancy or within 6 months after delivery. The cause is unclear, but immune and viral causes have been postulated. The course of the disease is variable; many cases improve or resolve completely over several months, but others progress to refractory heart failure. Immunosuppressive therapy has been advocated, but few supportive data are available. Recently, ß-blockers have been administered judiciously to these patients, with at least anecdotal success. Recurrence in subsequent pregnancies is common, particularly if cardiac function has not recovered.

Coronary Artery & Other Vascular Abnormalities

There have been a number of reports of myocardial infarction during pregnancy. It is known that pregnancy predisposes to dissection of the aorta and other arteries, perhaps because of the accompanying connective tissue changes.

However, coronary artery dissection is responsible for only a minority of the infarctions, with the majority being caused by atherosclerotic coronary artery disease or coronary emboli. Most of the events occur near term or shortly following delivery. Clinical management is essentially similar to that of other patients with acute infarction.

SPECIAL PROBLEMS

Prophylaxis for Infective Endocarditis

Although there is no universal agreement, many authorities recommend antibiotic prophylaxis during labor for patients at risk for endocarditis, especially if forceps delivery is anticipated or episiotomy is employed. Ampicillin (2 g intravenously or intramuscularly) plus gentamicin (1.5 mg/kg intravenously or intramuscularly [up to 80 mg]) followed by amoxicillin, 1.5 g orally every 6 hours, is the recommended regimen.

Management of Labor

Although vaginal delivery is usually well tolerated, unstable patients (including patients with severe hypertension and worsening heart failure) should have cesarean section. An increased risk of aortic rupture has been noted during delivery in patients with coarctation of the aorta and severe aortic root dilation with Marfan's syndrome, and vaginal delivery should be avoided in these conditions.

Cardiovascular Drugs during Pregnancy

Experience during pregnancy with many drugs is limited, and the effect on the fetus is often not well defined. Drugs with known potential for teratogenicity or fetal injury include phenytoin and the ACE inhibitors. Warfarin also presents a risk, but - at least in patients with prosthetic heart valves - many recommend that it be continued until the final 2 weeks. Self-injected low-molecular-weight heparin may be a good alternative, but data regarding efficacy and safety are lacking. Other than antihypertensive agents, which have been discussed above, cardiac drugs that appear safe during pregnancy include the digitalis glycosides, quinidine, procainamide, lidocaine, and short-term verapamil.