Purpose: Megacystis Microcolon Intestinal Hypoperistalsis Syndrome (MMIHS) is a congenital disease, and the etiology of the disease is unclear. It is speculated that maternal ingestion of some drugs during pregnancy and degeneration of smooth muscle cells in the fetus may be an etiologic factor. In this study we aimed to investigate the effect of maternal ingestion of bromide on the fetal bladder and colon in pregnant rats. Method: We separated animals into a bromide group including 30 rats and a control group with 14 rats. Nothing was given to the control group during pregnancy. Intraperitoneally 8 mg/kg/day bromide was given to the study group from the 6th to 12th day of pregnancy. All of the rats were sacrified on the 20th day of pregnancy. Histopathological examination of fetal colons and bladders was performed. Results: In the bromide group, an increase in the colon and bladder diameter, an increase in muscle atrophy in the colon and bladder wall, an increase in vacuolar degeneration in the muscles of the bladder and colon wall, and a significant decrease in ganglion cell numbers in the myenteric plexus of the colon and bladder were determined. Conclusion: In our rat model, we found histological structural changes in the rats' colon and bladder walls as a result of using bromide on the 6-12th days of pregnancy similar to pathological findings found in some of MMIHS patients' bowels and bladders.