A lot of small bumps on the back of pregnant women may be caused by acne, folliculitis and other diseases. 1. Acne: the onset of acne is often considered and androgen levels increase, bacterial infections and inflammatory reactions and other factors related to its preferred parts of the head, face, chest and back, lesions are often manifested as pimples, pimples, etc., the hormone level of the body after pregnancy has changed, which can lead to acne back, appearing a lot of small pimples. 2. Folliculitis: Folliculitis may be caused by pathogens such as Staphylococcus aureus infecting the hair follicles, and may be triggered by factors such as skin damage, excessive sweating and obesity. Typical symptoms are red papules or pustules, the most common parts of the head, face, trunk and other places. If the hair follicles behind the back are infected by pathogens during pregnancy, many small bumps will appear. The causes of many small bumps on the back of pregnant women are not one, and patients are advised to go to a regular hospital to clarify the cause of the disease.