The world health organization (WHO) classification of pulmonary hypertension has been redefined and updated in 2009 () [18
]. Idiopathic PAH and PAH associated with connective tissue disease affect predominantly women of childbearing age [18
]. Idiopathic PAH is rare and a rapidly progressive disease with an untreated survival of only 2.8 years [19
]. The association of PAH with connective tissue disease is a common phenomenon. The highest incidence of the development of PAH is known in scleroderma patients, especially with the CREST syndrome (10–20% develop PAH) followed by systemic lupus erythematous (SLE, 10%) [20
]. Patients with PAH in connective tissue disease have a deleterious clinical course and a worse prognosis [18
Venice clinical classification of pulmonary hypertension (2003).
WHO group 1 also includes PAH associated with congenital heart disease (CHD). The disease could be further classified based on anatomic pathophysiology of shunts or clinical phenotypes (Tables and ). A significant proportion of patients with CHD, in particular those with relevant systemic-to-pulmonary shunts, will develop PAH if left untreated [18
]. Hemodynamic changes during pregnancy can exacerbate the problems associated with CHD as well. In the Eisenmenger syndrome, right to left shunting increases during pregnancy because of systemic vasodilation and RV overload with decrease in pulmonary blood flow and increase cyanosis. The outcome is related to functional class (NYHA classification), the nature of the disease, and previous cardiac surgery. Any patient in functional class III or IV during pregnancy is at high risk whatever the underlying condition as this means there is no remaining cardiovascular reserve [5
]. The high-risk conditions are fragile aortas as in Marfan syndrome, left sided obstructions, and already dilated poorly functioning left ventricles [9
Anatomic-pathophysiologic classification of congenital systemic-to-pulmonary shunts associated with pulmonary arterial hypertension.
Clinical classification of congenital systemic-to-pulmonary shunts associated with PAH.
Pregnancy is often fatal for a PAH patient. In a retrospective review study from 1978 to 1996, mortality was 30% in IPAH, 36% in Eisenmenger's syndrome, and 56% in PH secondary to other conditions [1
]. A systemic review of all published reports from 1997 to 2007 of pregnancies in women with PAH found that overall maternal mortality was lower than previous reports, thought may be attributable to use of targeted PAH therapies and improved understanding of the disease. Mortality was 17% in IPAH, 28% in PAH associated with congenital heart disease, and 33% in PAH of other etiologies [21
]. A recent prospective, multinational registry that included 26 pregnancies reported improved mortality in well-controlled and particularly long-term responders to calcium channel blockers [22
]. Venous thromboembolism affects pregnant women 5 times more frequently than nonpregnant women of similar age [10
]. Pulmonary embolism has surpassed infection, hemorrhage, and preeclampsia/eclampsia to become a leading cause of manternal mortality in the United States [10
]. Amniotic fluid embolism (AFE) is a rare but catastrophic complication unique to pregnancy. Despite variation in reported incidence and mortality, AFE remains a life-threatening condition with significant morbidity and mortality for the pregnant women [15
]. It is the 5th most common cause of maternal mortality in the world [15