Pulmonary hypertension is categorized into mild, moderate, and severe stages. If it is mild pulmonary hypertension, pregnancy generally does not have a major impact. However, for those with moderate or especially severe pulmonary hypertension, pregnancy can be very dangerous for both the mother and the fetus. As the fetus grows, pulmonary hypertension can lead to ischemia and hypoxia, which can worsen over time. The mother is likely to develop symptoms of acute heart failure, severely endangering her life. Additionally, it can cause intrauterine hypoxia for the fetus, leading to miscarriage or stillbirth. Therefore, pregnancy is not recommended for patients with moderate, and particularly severe, pulmonary hypertension.