A 48 year old female who has recently started a new relationship comes to ask you for contraception. She has regular periods, denies any abnormal bleeding and is up to date with her smears. She does not use any form of contraception currently. She is a non-smoker and only occasionally drinks alcohol. After counselling, she has opted to commence the Progestogen only Pill (POP), Desogestrel.
Which one of the following statements is least correct?