Primary pulmonary hypertension is a disease of young women, usually in their child-bearing years. It carries a very high mortality rate. Patients present with severe dyspnea and syncope, and it has occurred during pregnancy. It is unknown if this is just an association or if pregnancy exacerbates the disease. If one suspects primary pulmonary hypertension, it is critical to eliminate other catastrophic events in the differential diagnosis that can complicate pregnancy such as amniotic fluid embolism, trophoblastic or air embolism, pulmonary thromboembolism, pulmonary veno-occlusive disease, and Eisenmengers syndrome. website
Fortunately, pulmonary thromboembolism is not common during pregnancy, since it is such a major management problem when it does occur. Deep venous thrombosis occurs in about 2/1,000 pregnancies and superficial thrombophlebitis in 12/1,000. The risk for pulmonary embolism is greatest in the first month postpartum, especially one to three days after delivery. The coagulation factor concentrations, especially 7, 9, and 10, are elevated during the entire pregnancy. We must consider all the potential risk benefit decisions involved in performing perfusion scans or angiography in these patients. Perfusion scans can be done with one-quarter to one-half the routine dose to reduce radiation risk. Ventilation scanning can be reserved only for the evaluation of positive perfusion scans. Iodine-labeled fibrinogen studies are contraindicated (fetal goiter effect).
The use of heparin and warfarin (Coumadin) is hazardous, and anticoagulation is a difficult task. Coumadin should not be used at all during the first trimester because it causes fetal embryopathy. It also can cause a fetal hemorrhage syndrome at birth, with an 18 percent perinatal mortality. Coumadin should be avoided in nursing mothers. Heparin, on the other hand, does not cross the placenta and does not affect the fetus. However, there is an increase in maternal hemorrhage at birth with heparinization.