Factor VIII (FVIII)

This is an observational research study to find out if there is a difference in the way children with moderate or severe hemophilia A, treated on two different types of factor replacement, form a clot and also evaluate if they develop tiny bleeds within the joint and subsequently early joint changes when receiving extended half-life factor VIII.

This study longitudinally observes the intergenerational (mother-child) continuum in hemophilia A from pregnancy through early childhood. Because the study follows mother-child pairs, the study includes both a maternal cohort and a pediatric cohort. Each cohort has a primary goal: for the mother with a severe hemophilia genotype, the overarching primary goal is to understand the risks for pregnancy-associated bleeding and postpartum hemorrhage (PPH); for the child, the overarching primary goal is to understand the risks, timing, and circumstances of development of anti-FVIII antibodies. From a longitudinal perspective, risks for both bleeding in the mother and anti-FVIII antibody development in the child are expected to be influenced over time by genetic and environmental factors that begin early in (or before) pregnancy. Enrollment of blood relatives is offered to improve power to better understand inherited contributions to bleeding and inhibitor development in the mother-baby pairs.