Pregnancy and heart disease

August 3, 2011

Pregnancy imposes a 30-50% increase in the amount of blood pumped by the mother’s heart to the uterus and the baby, especially after second trimester. Labor imposes extra effort on the heart because of large changes in the circulating blood volume. Normally, this increase in heart activity is well tolerated by the mother. However, certain patients with preexistent heart disease, such as valvular heart disease (mitral stenosis, MS), pulmonary hypertension (high blood pressure in the arteries of the lung), some forms of congenital heart disease, and patients with chronic heart failure, may not tolerate well the cardiac changes related to pregnancy. Therefore, in a few women with severe heart disease, pregnancy may be contraindicated because of high risk for both fetal and maternal morbidity and mortality.

Furthermore, some women even with milder forms of congenital heart disease have an increased risk of congenital heart disease in the baby. All women with preexistent cardiac disease should undergo cardiac counseling when pregnancy is contemplated. Most women with valvular or congenital heart disease will require antibiotic prophylaxis prior to delivery. Women with mitral valve prolapse and mild valvular heart disease tolerate pregnancy very well. (These are both conditions where the valves of the heart have abnormal shape/structure.)

A particular heart disease not well tolerated during pregnancy is rheumatic heart disease. Women constitute 75% of the population with rheumatic mitral valve disease. Women with moderate to severe rheumatic MS or aortic stenosis (AS) are at increased risk of worsening heart failure and fetal loss. These patients, usually with severe symptoms, are advised to undergo valve repair or replacement prior to pregnancy. In severe MS, the increased blood volume and tachycardia (rapid heart beat) associated with pregnancy and labor will aggravate the blood stasis (pooling or sluggish movement of the blood) in the lung, can aggravate pulmonary hypertension, and trigger atrial fibrillation (rapid/”fluttering” irregular heart rate) and acute pulmonary edema (fluid accumulation in the lungs), a potentially lethal complication of MS. In these situations, some women may be candidates for balloon mitral valvuloplasty (a procedure performed in the cardiac catheterization laboratory), which can increase the mitral valve opening and alleviate symptoms during pregnancy. Although surgery on the mitral valve can be performed during pregnancy, open-heart surgery increases the risk of abortion and fetal damage.

Another disease that poses an increased risk of cardiovascular manifestations in both the mother and the fetus is systemic lupus erythematosus (SLE). Systemic lupus erythematosus can be exacerbated by pregnancy, can cause fetal death, and can trigger congenital complete heart block in the baby. Although it is debated whether Systemic lupus erythematosus is triggered by pregnancy, clearly if the woman becomes pregnant during an active Systemic lupus erythematosus flare, this can be a serious burden for both the baby and the mother. Most immunosuppressive therapy cannot be safely used due to serious fetal side effects; 20-30% of women with active Systemic lupus erythematosus have miscarriage with fetal loss in up to 50%. The presence of high levels of specific antibodies during pregnancy confers a 5% risk of congenital complete heart block in the fetus; often the baby requires a pacemaker implantation immediately after delivery. One frequent complication of pregnancy in Systemic lupus erythematosus is the development of pre-eclampsia (hypertension during the second half of pregnancy). This is more likely to occur in women who have history of renal disease, hypertension, diabetes mellitus, preeclampsia, and antiphospholipid antibodies. As a result of all these potential problems, women with Systemic lupus erythematosus are encouraged to delay pregnancy until the disease has been inactive for at least 6 months.

SEE ALSO: Acute myocardial infarction, Cholesterol, Coronary risk factors, Diabetes, Hormone replacement therapy, Hypertension, Oral contraception, Smoking, Stroke, Systemic lupus erythematosus, Venous thromboembolism

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Category: Cardiovascular Disease