wishes - the antagonist drugs are either Orgalutron or Cetrotide - they basically stop any type of surge of luteinising hormone. they are taken every 24 hours until they're ready to trigger your ovulation, and cost around $100 a day (ball park) so it's an extra expense for you and one the doctor will probably try to avoid if possible

as to flare cycle - it's similar to a down reg cycle but they go off your natural AF - sometimes they can't get as much control over your hormones as they can't guarantee that your hormones are essentially "flat lined" before they start you on synarel...

antagonist cycle usually goes off your natural AF (well, for me that's what i was told) - they don't do any down reg at all (so no synarel, no pill) - for me, what they did was to try to force a bleed (i have no natural cycle) and when that didn't work (stubborn body!) the then did a blood test to make sure my hormones were essentially flat (similar to day one or two of AF), then started me injecting puregon (similar to gonal f). after 7 days, i was scanned for follicular growth, and either put on the antagonist meds for a few days to allow more growth (to get to optimal size) or, as it has been for a couple of my IUI cycles, we simply did two more days of jabs and then triggered ovulation. for IVF, i started cetrotide or orgalutron (can't remember which) on day 7 automatically, had scan on day 9 and BT on day 9, triggered ovulation day 11 for EPU day 13...

hope that helps - it can be very confusing when so many terms are being thrown at you from everyone and you're still in the dark - and given you were talking to the nurse on the phone, it's hard to say "hang on, give me more detail"!