Hereditary hemorrhagic telangiectasia and pregnancy: potential adverse events and pregnancy outcomes

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant condition with a prevalence of ~1 in 5,000 individuals. The pathophysiology of this condition centers on the lack of capillary beds between arterioles and venules, leading to direct contact between these vessels. This results in telangiectases on characteristic locations such as the face, fingers, mouth, and nasal mucosa. Visceral arteriovenous malformations (AVMs) are also observed in many patients, and these are most commonly seen in the brain, gastrointestinal tract, and lungs. Liver AVMs are present in many patients with HHT, though these individuals are usually asymptomatic; however, liver AVMs may lead to serious complications, such as high output cardiac failure. Diagnosis of HHT hinges upon fulfilling three out of four criteria: family history of the condition, mucocutaneous telangiectases, spontaneous and recurrent episodes of epistaxis, and visceral AVMs. Management is guided by international consensus guidelines and targets patients' specific AVMs. Prognosis is good, though severe complications including hemorrhage and paradoxical emboli are possible. Novel therapeutics are being explored in clinical trials; bevacizumab and pazopanib inhibit angiogenesis, while thalidomide bolsters blood vessel maturation. Pregnancy in patients with HHT is considered high risk. While the majority of pregnancies proceed normally, severe complications have been reported in some women with HHT; these include heart failure, intracranial hemorrhage, pulmonary hemorrhage, and stroke. Such complications occur most often in the second and third trimesters when maternal changes such as peripheral vasodilation and increased cardiac output are at their maximum. Awareness of the diagnosis of HHT has been associated with improved outcomes in pregnancy. Management guidelines for pregnant patients with HHT are reviewed.