IVF treatment should not be postponed for patients with high basal FSH concentrations

This study determined the influence of inter-cycle variation of basal FSH concentrations on IVF treatment results, in patients with a history of high basal FSH. Patients underwent at least two IVF cycles, one with basal serum FSH ⩾10 IU/l and the other at least 3 IU/l lower (interval between cycles being <1 year when the second cycle had the elevated FSH). A subanalysis was performed in patients with exceptionally large differences in values (⩾16 IU/l and ⩽12 IU/l). IVF outcomes were compared according to basal FSH concentrations in two consecutive cycles. Seventy-six patients met the inclusion criteria. Mean basal serum FSH were 15.0 ± 3.6 IU/l in the ‘high FSH’ group (range 12–24 IU/l) and 9.0 ± 3.0 IU/l in the ‘low FSH’ group (range 5–14 IU/l). Patient age, oestradiol at HCG administration, number of collected oocytes, fertilization and clinical pregnancy rates were similar for all cycles compared. Analysis of the subgroup with exceptionally large differences of basal FSH concentration yielded similar results. Neither high nor low basal serum FSH values were associated with IVF outcome in patients with reduced ovarian reserve and previously determined high basal FSH concentrations. Ovarian stimulation need not be delayed until FSH declines.