Progesterone Profiles in Pregnant, Non-Pregnant, Natural and Stimulated IVF Cycles with and Without Luteal Support

(1) To describe the progesterone profiles following pituitary down regulation in stimulated IVF cycles with the use of GnRH-a (2) To assess the impact of progesterone supplement and pregnancy on the subsequent luteal phase.

A prospective observational study performed in a specialist infertility clinic based at a tertiary centre in the north of England. Subjects were divided into cohorts depending on their treatment (natural or stimulated IVF cycles), the type of luteal support (nil or Progesterone) and eventual outcome (successful pregnancy or failure to conceive). Saliva Progesterone concentrations were the only measuring outcome.

Natural versus stimulated cycle (SIVF); As expected saliva progesterone concentrations were significantly higher in subjects undergoing SIVF than in the natural cycle from day 1 to day 6 of the cycle (P<0.001) but thereafter stimulated cycle concentrations declined prematurely to fall below those of the natural cycle group by day 7, becoming significantly lower than natural cycle concentrations by days 9 and 10 (P<0.01). With and without progesterone supplementation; Saliva progesterone concentrations in subjects undergoing NIVF and receiving progesterone supplement were 2.5-3 times greater than those concentrations seen in the unsupplementated natural cycle (P<0.001). Similarly in the SIVF-Progesterone supplemented group, saliva concentrations remained significantly higher (P<0.001) than in the unsupplemented cycle throughout luteal phase. Despite this, luteal supplementation did not prevent nor reverse the acute mid luteal (day 7) decline in progesterone seen in all stimulated cycles.

Luteal phase following pituitary down regulation is grossly abnormal. The timing and degree of luteal support routinely provided following stimulated IVF is not effective in 'correcting' the progesterone profile.