IGF1 and retinopathy of prematurity: Meta-analysis suggests that thrombocytopenia is associated with the development of ROP [SMD (95% CI) of -.62 [-.86, -.37], <i>p</i> < .001].<h4>Conclusion</h4>Low levels of serum IGF-1, high levels of serum glucose and thrombocytopenia all appear to have the strongest association with the development of ROP out of the 63 biomarkers investigated in this review.