How much can switching birth control method affect your cycle? went from nuvaring to bc pill for 1 month & back to nuvaring. late period in 1st month

A lot: Switching Birth control methods can wreak havoc on your menstrual cycle. It can take 2-3 months for your body to adjust to the new program. Best wishes!

Somewhat: Both products have estrogen and progestin but the progestins are slightly different & absorption rate is a different. Both recommend being consistent with time of day dosing or insertion. I would not be surprised by a 3-5 days late, but would not expect you to miss a period all together. If that happened, please check a pregnancy test. Good luck.