Risk factors of retinopathy of prematurity in extremely low birth weight infants by strictly controlling oxygen inhalation after birth

Abstract

Objective: To observe the incidence and severity of retinopathy of prematurity (ROP) in extremely low birth weight (ELBW) infants by strictly controlling the risk factors of ROP, such as oxygen inhalation after birth, to explore the related factors of ROP in ELBW infants. Methods: This was a cross-sectional study. 166 ELBW infants underwent neonatal screening were enrolled in this study, whose birth weight was less than 1 000 g. There were 79 males and 87 females infants, whose average gestational age was (27.99±1.73)weeks, and average birth weight was (904.45±80.23)g. According to the final screening results, the ELBW infants were grouped as follows: (1)ROP group and non-ROP group; (2)severe ROP group and mild or no ROP group. Risk factors included gestational age, birth weight, test-tube infants, fetuses number, complications during pregnancy, delivery mode and Apgar scores in 1 to 10 minutes, weight and weight gain proportion at 1-6 weeks after birth, postnatal feeding mode, history of oxygen inhalation, anemia and blood transfusion, and other systemic diseases were recorded. And their correlation with severe ROP was analyzed by SPSS 20.0 statistical software. Results: Ninty-four (56.63%) ELBW infants developed ROP, 16 (9.64%) were severe ROP and 14(8.43%) received treatment. Average birth weight between ROP group (911.95±72.80)g and non-ROP group (894.67±88.58)g had no difference(t=1.379, P=0.170). Average gestational age between ROP group (27.49±1.53) weeks and non-ROP group (28.64±1.76) weeks had significant difference(t=-4.491,P<0.001).And pregnancy-induced hypertension during pregnancy (χ(2)=4.479, P=0.034), Apgar score in 5 minutes (t=-2.760, P=0.006) and 10 minutes (t=-2.099, P=0.043), pneumonia (χ(2)=6.233, P=0.013), neonatal pneumonia (χ(2)=18.026, P<0.001) had significant difference between ROP group and non-ROP group. There was no effect on weight (F=0.009,P=0.753) or weight gain proportion (F=2.394,P=0.124) at 1-6 weeks after birth in ELBW infants with or without ROP. Average birth weight between severe ROP group(875.63±74.85)g and mild or no ROP group(907.53±80.41)g had no difference(t=-1.518, P=0.131).Average gestational age between severe ROP group(26.88±1.31)weeks and mild or no ROP group (28.11±1.73)weeks had significant difference(t=-2.766,P=0.006).And only fundus hemorrhage (χ(2)=4.507,P=0.034) had significant difference between severe ROP group and mild or no ROP group. There was no effect on weight (F=2.683,P=0.103) or weight gain proportion (F=0.431,P=0.513) at 1-6 weeks after birth in ELBW infants with or without ROP. Logistic regression analysis revealed that only gestational age was correlated to the incidence (β=-0.437,P<0.001) and severity (β=-0.616,P=0.007) of ROP significantly. Conclusion: By strictly controlling the risk factors of ROP, such as oxygen inhalation after birth, the severe rate of ROP in ELBW infants is low. However, gestational age is still the inevitable independent high risk factor for the incidence of ROP in ELBW infants. (Chin J Ophthalmol, 2019, 55:280-288).