Background: Hypoxic ischemic encephalopathy continues to be a significant cause of death and disability worldwide. Erythropoietin (EPO) has the potential to lessen neurologic sequelae due to hypoxia ischemia. Methods: The in vitro effects of EPO on total embryonic development and brain VEGF receptor (VEGFR) expressions were investigated in 50 rat embryos at 9.5 days of gestation that were cultured in whole rat serum (WRS). According to the study protocol, the embryos were divided into two groups. The first group is comprised hypoxia, 100 and 50 U/ml EPO after hypoxia groups. Group 2 comprised control (WRS) and WRS EPO. After 48-h culture, the embryos from each group were harvested to be analyzed according to a morphological scoring system and also genetically to measure brain VEGFR expression. Results: The mean morphological scores for the embryos grown in control, WRS + EPO, hypoxia, and in the presence of 100 and 50 U/ml EPO in hypoxic medium were 55.30 +/- 7.22, 52.10 +/- 5.27, 23.0 +/- 4.60, 36.20 +/- 5.07, and 19.70 +/- 5.07, respectively. Expressions of VEGFR-1, -2, -3 were significantly elevated in the 100 Wail EPO and WRS + EPO groups compared to the hypoxia group (p < 0.05). Conclusions: These results support the conclusion that (1) VEGFR-1, -2, -3 may increase with EPO treatment in hypoxic conditions, (2) VEGF and EPO may be part of a selfregulated physiological protection mechanism to prevent neuronal injury including in utero neural tube defects. (C) 2014 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.