The following is a summary of the “Endometriosis patients benefit from high serum progesterone in hormone replacement therapy–frozen embryo transfer cycles: a cohort study,” published in the Jan 2023 issue of Reproductive Biomedicine Online by Alsbjerg, et al.

Laparoscopy or ultrasound in patients with visible endometriomas confirmed the diagnosis of endometriosis in all 179 patients in this cohort study. Pretreatment included 42 days of oral contraceptives, a 5-day washout period, and then daily dosing with 6 mg of oral estrogen. When the thickness of the endometrium reached 7 mm or more, exogenous progesterone supplementation with vaginal progesterone gel 90 mg/12h was initiated. 

Patients began receiving 50 mg of intramuscular progesterone daily on the fourth day of vaginal progesterone supplementation. On day 6 of progesterone supplementation, the blastocyst transfer would take place. About 60% of pregnancies ended in a positive HCG result, 39% in a live birth rate (LBR), and 34% in a total loss rate. Therefore, the maximum Youden index value of 118 nmol/l (37.1 ng/ml) was the optimal progesterone cut-off level. 

Compared to patients with a progesterone level of less than 118 nmol/l, those with a progesterone level of 118 nmol/l or higher had a significantly higher live birth rate (LBR; 51% [44/86] vs. 34% [59/176], P = 0.01), while the adjusted odds ratio for live birth was 2.1 (95% CI 1.2 to 3.7). There is a threshold for optimal serum progesterone, as LBR was significantly higher at serum progesterone levels above 118 nmol/l (37.1ng/ml) than at lower serum progesterone levels.

Source: sciencedirect.com/science/article/pii/S1472648322006964