Background: Elevated follicle stimulating hormone (FSH) is associated with poor vaginal oocyte retrieval (VOR) outcomes and cycle cancellations but intercycle variability in basal FSH reportedly does not predict ovarian response.
Methods: We conducted a retrospective cohort study of basal FSH (n = 15573 cycles) in couples (n = 9132) who initiated IVF cycle(s) with basal estradiol (E2) <100 pg/mL between 2002 and 2014 to reevaluate this hypothesis. The most recent (current) FSH, maximum FSH (Max FSH) and prior cycle maximum basal FSH (PMax FSH) were computed for each cycle. Metaphase II (MII) oocyte counts were modeled by age, stimulation type, prior peak E2 level, prior MII count, Max FSH, PMax FSH and current FSH. Antral follicle counts, pregnancy, clinical pregnancy and live birth rates were modeled as secondary outcomes.
Results: Max FSH level distinguished completed cycles from cancelled cycles better than PMax FSH or current FSH (AUC of 0.72, 0.71 and 0.61, respectively, p < 0.001). Fewer MIIs were retrieved (5.7 ± 3.8) in cycles with Max FSH >13 mIU/mL (n = 1475) than those with ≤13 mIU/mL (n = 11978) (11.6 ± 7.1) (p < 0.001). Max FSH was a better predictor of MII count than PMax FSH or current FSH after controlling for age, stimulation type, prior peak E2 level and prior MII count. Additional MIIs were retrieved on average in cycles with PMax FSH >13 mIU/mL (n = 1930) whose current FSH was ≤13 mIU/ml rather than >13 mIU/ml (p < 0.01) after controlling for age, cycle number and stimulation type. However, no improvement in pregnancy or live birth rate was detected.
Conclusions: Max FSH is the best FSH-based predictor of ovarian reserve. Retrieval benefits from waiting for a "better" month appear to exist but are limited.
Elevated follicle stimulating hormone (FSH) measurements are associated with more frequent in vitro fertilization (IVF) cycle cancellations and fewer oocytes (eggs) being retrieved. It has been thought that a patient with an elevated FSH in the past would not have more oocytes retrieved if her FSH decreased in a subsequent cycle rather than remain elevated. We questioned this belief in a study of over 9132 couples who used IVF between 2002 and 2014. We assessed the effect of a patient's set of FSH measurements on her future outcomes, carefully focusing on 1930 cycles with a previously elevated FSH.
We found that the patient's highest FSH was the best predictor of cycle cancellations and the number of oocytes retrieved. However, even after controlling for the highest FSH, a patient was predicted to obtain slightly more oocytes at retrieval if her FSH decreased. However, we did not detect any improvement in pregnancy or live birth rates.
Retrieval benefits from waiting for a "better" month appear to exist but are limited.
Capsule: Highest historical FSH levels better predict cancellations and VOR counts than cycle-specific FSH, but waiting for a cycle with lower basal FSH still enhances retrieval outcomes.
Electronic supplementary material: The online version of this article (doi:10.1186/s12958-015-0078-0) contains supplementary material, which is available to authorized users.