The polyethylene-glycol (PEG) precipitation assay was used to examine the sera of sixty-nine pregnant women, thirty with normal pregnancies, ten with toxaemia of pregnancy, eleven with pregnancy complicated by diabetes and eighteen with case histories of recurrent abortions in order to find evidence of eventual circulating immune complexes (CIC). CIC were not seen in normal pregnancies, but were found in two of the toxaemic group, in two of those with recurrent abortions and in two of those with diabetes. After delivery, these six positive cases were all negative. The presence of CIC may have a determining role in the pathogenesis of some of the cases of the above conditions
