Winter Season of Conception Associated with an Increased Risk for Retinopathy of Prematurity (ROP)
Michael B. Yang, MD; Gui-Shuang Ying, PhD; Lauren A. Tomlinson, BS; Gil Binenbaum, MD; G-ROP Study Group
Abrahamson Pediatric Eye Institute, Cincinnati Children’s Hospital Medical Center
Introduction: Previous mouse studies found a melanopsin-dependent light-response pathway for retinal vascular development during early gestation (embryonic days E16-17). A single-center human study then found that lower average day-length during the first 90 days after conception was associated with increased risk of severe ROP. We sought to compare ROP risk when post-conceptual day 58 (correlates with mouse E16-17) falls near December 21 versus June 21, dates with minimum and maximum day lengths, respectively.
Methods: Secondary analysis was performed using retrospective data from the G-ROP Study, which included infants undergoing ROP screening at 29 North American hospitals in 2006-2012. Date of conception (DOC) was calculated as [(date of birth) – (estimated gestational age) + (14 days)], and 58 days were added (DOC+58). Prevalence of ROP for infants with DOC+58 within 90-day time windows centered on December 21 and June 21 were compared with multivariable logistic regression.
Results: 3740 infants had DOC+58 within the time windows studied. 885/1949 (45.4%) and 762/1791 (42.6%) of winter and summer conception infants, respectively, developed ROP (p=0.08). After adjustment for birth weight and gestational age, the odds of ROP for winter conception was 20% higher compared to summer conception (OR: 1.20; 95% CI: 1.01-1.42; p=0.03). The same association existed for 120-day time windows (OR:1.21, p=0.009).
Discussion: The increased ROP risk associated with winter conception may support a melanopsin-dependent light response for retinal vascular development.
Conclusion: If confirmed by additional studies, an interventional study of light therapy during early gestation may be considered to reduce ROP risk.
References: 1. Rao S, Chun C, Fan J, Kofron M, Yang MB, Hegde R, Ferrara N, Copenhagen DR, and Lang RA. A direct and melanopsin-dependent fetal light response regulates mouse eye development. Nature 494:243-6, 2013.
2. Yang MB, Rao S, Copenhagen DR, Lang RA. Length of Day during Early Gestation as an Independent Predictor of Risk for Severe Retinopathy of Prematurity. Ophthalmology 120:2706-13, 2013.