I girl I know has recently begun using Mesigyna, a monthly birth control injection available in Latin America. In the first three months of usage she reports having erratic periods. For example one began the twenty eighth of last month and now she says she is having one which began the ninth of this month. She says the nurse who has given her the injections has said this is completely normal for the first six months of usage. Can anyone confirm that erratic periods are a side effect of this or similar drugs?