The etiology of retinopathy of prematurity appears to be multifactoria
l. Introduction of new treatments in neonatal care may add new risk fa
ctors. We have analyzed the relationship between 42 perinatal factors
and the development of retinopathy of prematurity in 78 infants with a
birth weight < 1501 g and/or gestational age < 33 weeks. We have also
applied a chronological analysis of the maximum and minimum pO2 and p
CO2 values. Retinopathy of prematurity was seen in 37 of 78 infants (4
7.4%). Nineteen factors were found to be related to the development of
retinopathy of prematurity. However, when step-wise logistic regressi
on analysis was used, only birth weight, number of days of oxygen ther
apy and use of beta-blocking agents by the mother before birth were fo
und to be associated with the development of retinopathy of prematurit
y. The results suggest that medication with beta blockers immediately
before birth should be used cautiously.