Beta-cell hyperplasia in macrosomic infants and fetuses of nondiabetic mothers

The objective of this study was to test the hypothesis that macrosomic infa nts of nondiabetic mothers have beta-cell hyperplasia in their pancreases. Pancreatic tissues were examined from 10 macrosomic fetuses and liveborn in fants and from 10 comparison cases matched for gestational age and gender. None of the mothers had a history of diabetes and all had normal glucose sc reening during pregnancy. Tissues were stained with hematoxylin and eosin a nd a monoclonal antibody against beta cells and were analyzed using an imag e analysis program to evaluate the size and surface area of beta-cell clust ers. Brain/liver weight ratios were calculated and compared. The total surf ace area and cluster size of beta cells in the pancreases of macrosomic sub jects were significantly larger than in the comparison pancreases. The stud y subjects lacked macroscopic and histopathologic findings expected in infa nts of diabetic mothers. We conclude that some macrosomic fetuses and infan ts of nondiabetic mothers manifest beta-cell hyperplasia. This corresponds to the higher insulin levels in macrosomic infants of nondiabetic mothers d escribed in previous clinical studies. In macrosomic fetuses the stimulus f or beta-cell hyperplasia may not involve aberrant maternal glucose levels.