Outcomes of pregnancies affected by hemoglobin H disease

To determine the outcomes of pregnancies affected by hemoglobin H (HbH) disease. A retrospective cohort study was conducted with 120 women with singleton pregnancies complicated by HbH disease only. The controls-to-cases ratio was 2:1. Maternal outcomes were similar in the 2 groups. The incidences of fetal growth restriction (relative risk [RR], 2.4; 95% confidence interval [CI], 1.60-3.50), preterm birth (RR, 1.4; 95% CI, 1.03-1.96), and low birth weight (RR, 1.9; 95% CI, 1.46-2.56) were significantly higher in the study than in the control group. The perinatal mortality rate was slightly higher in the study group. In spite of attempts to keep hemoglobin levels sufficiently high (>7.0 g/dL), pregnancies with HbH disease were significantly associated with increased risks of fetal growth restriction, preterm birth, and low birth weight.