Postnatal closure of ductus venosus in preterm infants <= 32 weeks - An ultrasonographic study

Aim: To assess ultrasonographically the flow pattern and the time of postna tal closure of ductus venosus in preterm infants less than or equal to 32 w eeks. Methods: Thirty-three preterm infants less than or equal to 32 weeks were studied within the first 1 to 5 days of life and followed every second day with ultrasound until no flow was detected either through the ductus v enosus or the ductus arteriosus. Results: The ductus venosus was closed in only 9% by day 3, in 40% by day 8 and 88% by day 18. All were closed by day 37. This is significantly later than in healthy term neonates. Closure of the ductus venosus was not significantly correlated with closure of ductus arteriosus. Conclusion: The ductus venosus shows a delayed closure in prete rm infants, with no significant correlation to the closure of the ductus ar teriosus or the condition of the infant. We speculate that immaturity of th e ductus venosus and possibly increased levels of dilating prostaglandins l eads to a delayed obliteration of the vessel. An open ductus venosus repres ents a portocaval shunt and may have metabolical and pharmacological conseq uences. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.