Fetal Anemia With Persistent Pulmonary Hypertension: A Report of 3 Cases

Persistent pulmonary hypertension of the newborn after fetomaternal hemorrhage

BACKGROUND

Newborns with anemia are at increased risk of persistent pulmonary hypertension of the newborn (PPHN), yet reports on the association between fetomaternal hemorrhage (FMH) and PPHN are rare. To optimize care for pregnancies complicated by FMH, clinicians should be aware of the risks of FMH and the possible diagnostic and therapeutic options. To increase the current knowledge, the incidence of PPHN and short-term neurologic injury in FMH cases were studied.

STUDY DESIGN AND METHODS

We included all FMH cases (≥30 mL fetal blood transfused into the maternal circulation) admitted to our neonatal unit between 2006 and 2018. First, we evaluated the incidence of PPHN and short-term neurologic injury. Second, we studied the potential effect of intrauterine transfusion (IUT).

RESULTS

PPHN occurred in 37.9% of newborns (11 of 29), respectively, 14.3% (one of seven) and 45.5% (10 of 22) in the IUT group and no-IUT group (p = 0.20). The mortality rate was 13.8% (4 of 29). Severe brain injury occurred in 34.5% (10 of 29), respectively, and 14.3% (one of seven) and 40.9% (nine of 22) in the IUT group and no-IUT group (p = 0.37).

CONCLUSION

Awareness should be raised among perinatologists and neonatologists about the possible life-threatening consequences of FMH, as more than one-third of neonates with anemia due to FMH experience PPHN and suffer from severe brain injury. Antenatal treatment with IUT seems to reduce these risks. Specialists should therefore always consider fetal anemia in FMH cases and refer patients to a fetal therapy center. If anemia is present at birth, it should be corrected promptly and neonatologists should be aware of signs of PPHN.

Hematological disorders and pulmonary hypertension

Pulmonary hypertension (PH), a serious disorder with a high morbidity and mortality rate, is known to occur in a number of unrelated systemic diseases. Several hematological disorders such as sickle cell disease, thalassemia and myeloproliferative diseases develop PH which worsens the prognosis. Associated oxidant injury and vascular inflammation cause endothelial damage and dysfunction. Pulmonary vascular endothelial damage/dysfunction is an early event in PH resulting in the loss of vascular reactivity, activation of proliferative and antiapoptotic pathways leading to vascular remodeling, elevated pulmonary artery pressure, right ventricular hypertrophy and premature death. Hemolysis observed in hematological disorders leads to free hemoglobin which rapidly scavenges nitric oxide (NO), limiting its bioavailability, and leading to endothelial dysfunction. In addition, hemolysis releases arginase into the circulation which converts L-arginine to ornithine, thus bypassing NO production. Furthermore, treatments for hematological disorders such as immunosuppressive therapy, splenectomy, bone marrow transplantation, and radiation have been shown to contribute to the development of PH. Recent studies have shown deregulated iron homeostasis in patients with cardiopulmonary diseases including pulmonary arterial hypertension (PAH). Several studies have reported low iron levels in patients with idiopathic PAH, and iron deficiency is an important risk factor. This article reviews PH associated with hematological disorders and its mechanism; and iron homeostasis and its relevance to PH.