A median of 1.4 times and 1.8 times the odds of developing retinopathy of prematurity (ROP) were observed for every week decrease in gestational age (GA) and every 100-g decrease in birth weight (BW), respectively.

• In current national guidelines, GA and BW are used as their basis for ROP screening.

• This review was conducted to assess the strength of association of documented risk factors for ROP in large sample, population-based studies.

• From MEDLINE, EMBASE, and Cochrane Library, 18 studies with 342,005 infants were selected.

• In preterm infants, overall risk of ROP was estimated to be 18.8%.

• A median adjusted odds ratio (aOR) of 1.4 times (range 1.2–1.9) of developing ROP was reported for every week decrease in GA.

• Estimated median aOR was 1.8 times (range 1.2–2.7) for every 100-g decrease in BW.

• Infants with neonatal sepsis and bronchopulmonary dysplasia had higher risk.

• Risk of any, severe, and treatment-requiring ROP was shown to be the highest for 23 weeks GA, which was 66.5, 40.3, and 39.4%, respectively.

• Regions with higher neonatal mortality rates were found to have the highest mean GA of infants with ROP.