Table 2

Perinatal risk factors studied for potential association with the development of threshold ROP. Results are reported by incidence (%) or by mean and SD

ControlsCasesp Value
ROM  =  rupture of membranes; CLD  =  chronic lung disease; PDA  =  patent ductus arteriosus; EPO  =  erythropoietin; IVH  =  intraventricular haemorrhage; PNA  =  postnatal age; GA  =  gestational age.
Number of infants14035
Maternal factors
Assisted conception13%29%NS
Maternal hypertension13%6%NS
Tocolysis betamimetics64%69%NS
Tocolysis indomethacin10%11%NS
ROM>24 hours73%83%NS
Amnionitis47%34%NS
Caesarean45%48%NS
Multiple birth30%43%NS
At birth
Sex (boy)52%54%NS
Gestational age25.5 (0.7)25.2 (0.7)<0.005
Weight at birth (g)815 (155)743 (166)<0.05
Growth restricted (<10th)15%28%NS
Apgar 5 minutes7.7 (1.6)7.1 (1.3)<0.05
CRIB score5.3 (3.3)6.7 (2.9)<0.05
During neonatal stay
Intestinal perforation7%6%NS
Cholestasis14%23%NS
Breast feeding35%9%NS
Parenteral nutrition (days)38.7 (24.5)56.7 (28.8)<0.005
Surfactant administered74%77%NS
Ventilatory support (days)14.1 (15.6)25.1 (17.9)<0.005
Respiratory support (days)38.7 (23.4)57.9 (28.1)<0.005
Oxygen support (days)60.5 (53.4)89.5 (38.8)<0.005
CLD 28 days PNA79%94%<0.005
CLD 36 weeks GA39%66%<0.005
Systemic steroids56%80%<0.005
Treated PDA55%46%NS
Inotropics65%71%NS
IVH >grade 133%43%NS
Leucomalacia9%8%NS
Renal insufficiency15%46%<0.005
Phototherapy72%63%NS
Transfusions (number)6.4 (4.8)10.8 (5.3)<0.0005
EPO20%9%NS