First trimester explants (n=6) and purified term trophoblast cells (n=5) were cultured in the presence of cobalt chloride, a hypoxia mimetic. Purified term trophoblast cells from normal, C-section deliveries (n=6) were cultured in 2%, 8% or 21% oxygen for twenty-four hours. HA-1 mRNA expression, determined using qRT-PCR, was normalized to beta-actin and fold change relative to the untreated controls or 21% oxygen condition, as appropriate, was calculated using the ddCt method. HA-1 mRNA expression was elevated in the first trimester placental explants and purified term cytotrophoblast cells treated with 100μM cobalt chloride as compared to the untreated controls (P=0.04 and P<0.01, respectively). HA-1 mRNA expression was significantly higher in the 8% and 2% oxygen conditions as compared to 21% oxygen (P<0.01). HA-1 mRNA expression was also significantly higher in the 2% oxygen condition as compared to the 8% oxygen condition (P<0.01). *=P<0.01.