From what I understand, yes, nursing once a day affects prolactin levels. Twelve weeks is the expected window to get a period after weaning (if you haven't had one yet) and 6 weeks is usual, but it can take up to six months for prolactin levels to return to baseline after complete weaning. This is what my ob/gyn told me - I did extended bf (3 years) during which I never had a ppaf, so I asked a lot of questions! In my case, I had long suspected a problem (DS was going 12+ hours between feeds for the last year we nursed) and pushed for testing after 12 weeks, and it turned out I had a prolactinoma - a benign prolactin-secreting pituitary tumor. From my RE I have learned that some women will have regular cycles with the same prolactin levels that I had (moderately elevated), whereas I had complete amenorrhea. In other words, it is hard to guess your prolactin levels if you are cycling; they may still be elevated. If you have the opportunity and want to be reasonably unconcerned about prolactin, I would aim to wean 4-6 weeks before you start the protocol, but of course, ask your doctors' opinions. ETA: Whoops, just re-read your question and realized you may not have 4 weeks - I think it will still be okay because if you wean before starting the BCPs, you will have close to 4 weeks anyway, and the BCPs may help in that prolactin suppresses estrogen. Can you request prolactin b/w after you finish the BCPs? FYI, labs have quite different reference ranges for prolactin, so it's always worth asking what was used.
I agree with you, goldfinches. Btw, the meds you are referring to are either bromocriptine (Parlodel) or cabergoline (Dostinex).
ThankfulMama, hoping your upcoming IVF cycle goes well! I hope this will be helpful to you.