Progesterone level and progesterone/estradiol ratio on the day of hCG administration: detrimental cutoff levels and new treatment strategy.

Objective: To identify if there are certain cutoff levels for P and or the P/E(2) ratio on the day of hCG that would be defined as detrimental for occurrence of pregnancy in women with normal ovarian reserve undergoing cleavage-stage embryo transfer (ET). Secondarily, to determine if these same cutoffs might have the same potential negative effect in women undergoing blastocyst ET.

Design: Prospective cohort study including two randomized cohorts.

Setting: Private and university fertility centers.

Participant(s): A total of 240 women undergoing long agonist protocol with at least four grade 1 day 3 embryos.

Intervention(s): Women were randomized in a 1:1 ratio to undergo day 3 or day 5 embryo transfer.

Main Outcome Measure(s): Clinical pregnancy rate (CPR) was the primary outcome.

Result(s): Using receiver operator characteristics, cutoffs for P and P/E(2) ratio were 1.5 ng/mL and 0.55, respectively. Patients with P ≤ 1.5 ng/mL and P/E(2) ≤ 0.55 undergoing cleavage-stage ET had higher CPR. Using multiple regression, P/E(2) ratio was the only independent predictor for pregnancy. The P and P/E(2) cutoffs were not correlated with CPR in blastocyst transfers.

Conclusion(s): Progesterone >1.5 ng/mL and P/E(2) >0.55 affect the CPR in women undergoing cleavage-stage, but not blastocyst ET. P/E(2) ratio is the only independent prognosticator for cycle outcome in women undergoing cleavage-stage ET.