Risk for Retinopathy of Prematurity in Singletons versus Twins in a Colorado Cohort

Abstract

Purpose: We performed a retrospective cohort study on the records of newborns eligible for Retinopathy of Prematurity (ROP) screening using the 2013 screening criteria (less than 31 weeks’ gestation or birth weight ≤ 1500 grams). We hypothesized that singletons would have a higher incidence of high grade (Type 1 or Type 2) ROP than twins.

Methods: This study was performed on the records of 650 neonates (2008 to 2012) from two tertiary care neonatal intensive care units (University of Colorado Hospital and Children’s Hospital Colorado). We excluded the following records from the analysis: higher order multiples and incomplete charts (n = 14), low grade ROP (n = 116) and neonates who died before ROP screening commenced (n = 44). In the analytic dataset of 476 records, we examined if a singleton birth was a risk factor for ROP using the relative risk as a measure of association (P < 0.05).

Results: In the cohort (n=476), the overall incidence of high grade ROP was 12.6%. 113(24%) babies resulted from a multiple birth. . The number of newborns with high grade ROP in singletons and multiples was 50/363(13.8%) and 10/113 (8.8%), respectively. Although not significant, singletons were 1.5 times more likely to develop high grade ROP compared with multiples (95% Confidence Interval 0.8 to 2.8, P = 0.3). The mean ± SD gestational age (weeks) in singletons and multiples was 28.6 ±2.4 and 29.0±2.1 respectively (P = 0.05). The difference in mean birth weight (grams), accounting for clustering within mothers, between singletons and multiples was 1191.02 (SE=20.8) and 1228.24 (SE=38.5) respectively (P = 0.4).

Conclusions: In this cohort singleton deliveries were at an elevated risk for ROP. Further research is necessary on this cohort to investigate the role of other maternal and perinatal risk factors such as chorionicity of the placenta in ROP.