Thromboembolism in pregnant women with mechanical prosthetic heart valves anticoagulated with low molecular weight heparin

The pregnant cardiac woman

Cardiac diseases are present in 0.5-4% of pregnancies, and they remain a frequent cause of death during pregnancy. Pregnancy per se imposes significant hemodynamic changes, placing a major burden on the cardiovascular system. The early recognition and close follow-up of patients with cardiac diseases will improve maternal tolerance to the cardiovascular burden imposed by pregnancy, promote fetal growth and neonatal survival. Rheumatic heart disease remains the most frequent heart disease in the pregnant population with pulmonary edema as the most frequent complication. Atrial septal defect is the most frequent congenital heart disease in the adult population, whereas tetralogy of Fallot is the most common cyanotic congenital heart disease. An improvement in modern techniques of monitoring, a better understanding of the pathophysiology of cardiac disease, as well as multidisciplinary care has led to a substantial improvement in outcome of the pregnant cardiac patient. Management should be initiated before conception as it will provide optimal clinical conditions and sufficient information on the underlying pathophysiology.

Cardiac disease in pregnancy

Congenital heart disease in pregnancy is increasingly common because of the advances in surgery and medical therapy which have taken place over the last 30 years, which means that more affected women are surviving into the reproductive age. Antenatal counselling needs to be tailored to the specific lesion, with pulmonary hypertension and cyanotic disease presenting a risk of maternal mortality of up to 50%. The use of anticoagulants in women with artificial valves presents a particular challenge, heparin being safer for the baby and warfarin for the mother. Peripartum cardiomyopathy and Marfan's syndrome may be less dangerous than once thought. The risk of congenital heart disease in the fetus is increased, from twice to 20-fold, depending on the nature of the mother's lesion. Care throughout pregnancy and in the puerperium should be multidisciplinary and include cardiologists, obstetricians and midwives with experience of such cases, preferably in a tertiary centre.