For how many months did Elizabeth stay in seclusion after she conceived John?

Answer: Five

Elizabeth remained in seclusion for five months, saying the Lord had taken away her disgrace among the people.

“After these days, his wife Elizabeth became pregnant and for five months remained in seclusion. She declared, “The Lord has done this for me. In these days He has shown me favor and taken away my disgrace among the people.””— Luke 1:24-25 (BSB)