because a cluster of blood vessels in the brain called the germinal matrix is not yet fully developed, making it more fragile. Delivery at 24 weeks is considered to be the edge of viability by the ...

Abstract: Preterm neonates are vulnerable to periventricular-intraventricular hemorrhage since the periventricular germinal matrix blood vessels are still immature and fragile until around 36 weeks.

Adv Neonatal Care. 2005;5(1):14-27.