I started the birth control mononessa yesterday and took the pill today.when can my partner ejaculate in me without having a high risk of pregnancy. ?

Several factors: There is more than just one factor that determines what the likelihood is for a woman to conceive during the first cycle that she is on a birth control pill like Mononessa. It is best to use condoms during the first pill cycle - the second cycle will be safe.

1 week: The answer to that question depends on where you were in your cycle when you started Mononessa. In general, without knowing when you started, you should use a back-up method for 1 week after starting Mononessa. Best wishes!