Is measurement of progesterone level prior to FSH stimulation useful in GnRH-antagonist cycles?

Abstract

Aim: To reduce patient inconvenience during in vitro fertilization (IVF) cycles, some protocols delay intensive monitoring until mid-follicular stimulation. Others assess hormone levels prior to follicle-stimulating hormone (FSH) administration, not commencing stimulation until baseline progesterone (P4) levels (< 5 nmol/l) are achieved. Higher P4 levels (> 4.8 nmol/L) on the day of FSH trigger have been implicated in poorer pregnancy rates. This study evaluates the association of P4 levels at day 1-2 in gonadotrophin-releasing hormone (GnRH)-antagonist cycles with pre-trigger P4 levels and clinical pregnancy rates (CPRs).

Method: All fresh GnRH-antagonist IVF cycles between June 2011 and June 2012, in which pre-FSH P4 levels were not routinely performed (group 1), were retrieved from the IVF Australia database and compared with controls (group 2).

Results: There were 163 cycles in each group. P4 levels on the day of trigger were significantly higher in group 1 (3.75 vs. 2.77, p < 0.05). The incidence of pre-trigger P4 levels >4.8 nmol/l was significantly higher in group 1 (30 vs. 16, p < 0.05). The number of oocytes retrieved was higher in group 1 (11.1 vs. 9, p < 0.05), however fertilization rates were significantly lower in that group (53.6% vs. 61.2%, p < 0.05); CPRs were similar between the two groups (27.8% vs. 31.8%, p = ns). Overall, pregnancy rates were lower in cycles with pre-trigger P4 level of > 4.8 nmol/L compared with those with lower levels (15% vs. 32.5%, p < 0.05).

Conclusion: We found that measurement of P4 level at early follicular phase was associated with significantly lower pre-trigger levels. However, this did not translate into a difference in CPR between the monitored and unmonitored groups. We have confirmed that elevation in pre-trigger P4 level is associated with halving of the CPR, indicating that the most important P4 measurements are those in the late follicular/pre-trigger phase.

Keywords: gonadotrophin-releasing hormone antagonist/agonist; in vitro fertilization (IVF); progesterone.