Two bumps on the buttocks in the third trimester of pregnancy is not normal and may be caused by folliculitis, eczema and other diseases. 1. Folliculitis: Pregnant women may not clean their buttocks properly during pregnancy, which increases the risk of bacterial infection of the hair follicles on both sides of the buttocks and causes folliculitis, which leads to bumps on both sides of the buttocks under the stimulation of inflammation. 2. Eczema: pregnant women during pregnancy due to immune abnormalities caused by eczema symptoms on both sides of the buttocks, and then appear on both sides of the buttocks bumps phenomenon, sometimes may be accompanied by itching. More than three months pregnant with two bumps on the buttocks there are many other reasons, such as pregnant women during pregnancy, any discomfort, should go to the hospital in a timely manner, by the doctor for standardized treatment, so as not to delay the condition.