The placental protein 12 (PP 12) was found to be identical with the insulin like growth-factor binding protein (IGF-bp). In present investigations serum samples of 420 healthy pregnant women between 7th and 40th weeks of gestation were proved regarding to their IGF-bp concentrations by means of a radioimmunoassay. For each pregnancy week means and standard deviations were estimated. IGF-bp serum concentrations continuously increased up to the 18th week (140 +/- 40 micrograms/l); followed by decreasing of the values up to the 30th week (102 +/- 44 micrograms/l) and then slightly increased up to term (121 +/- 46 micrograms/l). In addition the IGF-bp estimations were performed in maternal serum samples of 45 diabetic pregnant women complicated by retinopathia diabetica benigna as well as proliferativa; sum total 101 serum samples. In patients with benign retinopathy 82% (12/68) and in patients of proliferative retinopathy 85% (5/33) of the IGF-bp values were increased above the two times standard deviation.