It is common to have a change in menstrual cycle while taking steroids. Both spotting and late or missed periods are possible. Being chemical contraceptives control menstruation I my male/non medical opinion there could be issues. Unless you are willing to chance getting pregnant I suggest dropping the birthcontrol and using an alternative method while on the winstrol.
The statements contained herein have not been evaluated by the Food and Drug Administration. The consumer comments and experiences relayed herein may not be typical. Your experience may vary.
Disclaimer: The advice I provide is based on experience and/or research and should not be considered professional medical advice. It is best to confirm any potential use of a drug or possible medical condition with a licensed doctor.