Placental protein 12 (PP 12), a decidual protein, in pregnancy complicated by diabetes with retinopathy.

Placental protein 12 (IGF-bp/PP 12) is a soluble tissue antigen produced in the decidua. PP 12 was measured in the 3rd trimester of diabetic pregnancy complicated by retinopathy. The mean values of the healthy control group between 28 and 34 and between 35 and 39 weeks gestation were 108 +/- 39 micrograms/l and 124 +/- 47 micrograms/l, respectively. The equivalent values in diabetic pregnancies complicated by retinopathy were 200 +/- 80 micrograms/l and 204 +/- 81 micrograms/l, respectively; both these PP 12 values were significantly (P less than 0.05) above the values in the control group. There was no significant difference between benign and proliferative retinopathy. The increased PP 12 levels in the presence of diabetic retinopathy are probably caused by decidual degeneration.