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

ObjectiveTo identify if there are certain cutoff levels for P and or the P/E2 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.DesignProspective cohort study including two randomized cohorts.SettingPrivate 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/E2 ratio were 1.5 ng/mL and 0.55, respectively. Patients with P ≤1.5 ng/mL and P/E2 ≤0.55 undergoing cleavage-stage ET had higher CPR. Using multiple regression, P/E2 ratio was the only independent predictor for pregnancy. The P and P/E2 cutoffs were not correlated with CPR in blastocyst transfers.Conclusion(s)Progesterone >1.5 ng/mL and P/E2 >0.55 affect the CPR in women undergoing cleavage-stage, but not blastocyst ET. P/E2 ratio is the only independent prognosticator for cycle outcome in women undergoing cleavage-stage ET.