Birth control pills sometimes mask perimenopause because the estrogen in the pills can hide the symptoms. Birth control pills have hormone levels that override our normal hormone levels. Somebody who is taking a birth control pill regularly would have regular bleeding and there may be hormone changes that are occurring that may not be apparent.

You would have to stop birth control pills to diagnose if someone is in menopause or not. This is the same with IUD and contraceptive implants that have hormones in them. The copper IUD does not contain hormones.