A drop in serum progesterone from oocyte pick-up +3 days to +5 days in fresh blastocyst transfer, using hCG-trigger and standard luteal support, is associated with lower ongoing pregnancy rates.

Do early- and mid-luteal serum progesterone (P4) levels impact ongoing pregnancy rates (OPRs) in fresh blastocyst transfer cycles using standard luteal phase support (LPS)? A drop in serum P4 level from oocyte pick-up (OPU) + 3 days to OPU + 5 days (negative ΔP4) is associated with a ∼2-fold decrease in OPRs. In fresh embryo transfer cycles, significant inter-individual variation occurs in serum P4 levels during the luteal phase, possibly due to differences in endogenous P4 production after hCG trigger and/or differences in bioavailability of exogenously administered progesterone (P) via different routes. Although exogenous P may alleviate this drop in serum P4 in fresh transfer cycles, there is a paucity of data exploring the possible impact on reproductive outcomes of a reduction in serum P4 levels. Using a prospective cohort study design, following the initial enrollment of 558 consecutive patients, 340 fulfilled the inclusion and exclusion criteria and were included in the final analysis. The inclusion criteria were: (i) female age ≤40 years, (ii) BMI ≤35 kg/m2, (iii) retrieval of ≥3 oocytes irrespective of ovarian reserve, (iv) the use of a GnRH-agonist or GnRH-antagonist protocol with recombinant hCG triggering (6500 IU), (v) standard LPS and (vi) fresh blastocyst transfer. The exclusion criteria were: (i) triggering with GnRH-agonist or GnRH-agonist plus recombinant hCG (dual trigger), (ii) circulating P4 >1.5 ng/ml on the day of trigger and (iii) cleavage stage embryo transfer. Each patient was included only once. The primary outcome was ongoing pregnancy (OP), as defined by pregnancy ≥12 weeks of gestational age. A GnRH-agonist (n = 53) or GnRH-antagonist (n = 287) protocol was used for ovarian stimulation. Vaginal progesterone gel (Crinone, 90 mg, 8%, Merck) once daily was used for LPS. Serum P4 levels were measured in all patients on five occasions: on the day of ovulation trigger, the day of OPU, OPU + 3 days, OPU + 5 days and OPU + 14 days; timing of blood sampling was standardized to be 3-5 h after the morning administration of vaginal progesterone gel. The delta P4 (ΔP4) level was calculated by subtracting the P4 level on the OPU + 3 days from the P4 level on the OPU + 5 days, resulting in either a positive or negative ΔP4. The median P4 (min-max) on the day of triggering, day of OPU, OPU + 3 days, OPU + 5 days and OPU + 14 days were 0.83 ng/ml (0.18-1.42), 5.81 ng/ml (0.80-22.72), 80.00 ng/ml (22.91-161.05), 85.91 ng/ml (15.66-171.78) and 13.46 ng/ml (0.18-185.00), respectively. Serum P4 levels uniformly increased from the day of OPU to OPU + 3 days in all patients; however, from OPU + 3 days to OPU + 5 days, some patients had a decrease (negative ΔP4; n = 116; 34.1%), whereas others had an increase (positive ΔP4; n = 220; 64.7%), in circulating P4 levels. Although the median (min-max) P4 levels on the day of triggering, the day of OPU, and OPU + 3 days were comparable between the negative ΔP4 and positive ΔP4 groups, patients in the former group had significantly lower P4 levels on OPU + 5 days [69.67 ng/ml (15.66-150.02) versus 100.51 ng/ml (26.41-171.78); P < 0.001] and OPU + 14 days [8.28 ng/ml (0.28-157.00) versus 19.01 ng/ml (0.18-185.00), respectively; P < 0.001]. A drop in P4 level from OPU + 3 days to OPU + 5 days (negative ΔP4) was seen in approximately one-third of patients and was associated with a significantly lower OPR when compared with positive ΔP4 counterparts [33.6% versus 49.1%, odds ratio (OR); 0.53, 95% CI; 0.33-0.84; P = 0.008]; this decrease in OPR was due to lower initial pregnancy rates rather than increased overall pregnancy loss rates. For negative ΔP4 patients, the magnitude of ΔP4 was a significant predictor of OP (adjusted AUC = 0.65; 95% CI; 0.59-0.71), with an optimum threshold of -8.73 ng/ml, sensitivity and specificity were 48.7% and 79.2%, respectively. BMI (OR; 1.128, 95% CI; 1.064-1.197) was the only significant predictor of having a negative ΔP4; the higher the BMI, the higher the risk of having a negative ΔP4. Among positive ΔP4 patients, the magnitude of ΔP4 was a weak predictor of OP (AUC = 0.56, 95% CI; 0.48-0.64). Logistic regression analysis showed that blastocyst morphology (OR; 5.686, 95% CI; 1.433-22.565; P = 0.013) and ΔP4 (OR; 1.013, 95% CI; 0.1001-1.024; P = 0.031), but not the serum P4 level on OPU + 5 days, were the independent predictors of OP. The physiological circadian pulsatile secretion of P4 during the mid-luteal phase is a limitation; however, blood sampling was standardized to reduce the impact of timing. Two measurements (OPU + 3 days and OPU + 5 days) of serum P4 may identify those patients with a drop in P4 (approximately one-third of patients) associated with ∼2-fold lower OPRs. Rescuing these IVF cycles with additional P supplementation or adopting a blastocyst freeze-all policy should be tested in future randomized controlled trials. None. S.C.E. declares receipt of unrestricted research grants from Merck and lecture fees from Merck and Med.E.A. P.H. has received unrestricted research grants from MSD and Merck, as well as honoraria for lectures from MSD, Merck, Gedeon-Richter, Theramex, and IBSA. H.Y. declares receipt of honorarium for lectures from Merck, IBSA and research grants from Merck and Ferring. The remaining authors declare that they have no conflict of interest. The study was registered at clinical trials.gov (NCT04128436).

Uyanik E ，Mumusoglu S ，Polat M ，Yarali Ozbek I ，Esteves SC ，Humaidan P ，Yarali H ... -  《-》

The BISTIM study: a randomized controlled trial comparing dual ovarian stimulation (duostim) with two conventional ovarian stimulations in poor ovarian responders undergoing IVF.

Is the total number of oocytes retrieved with dual ovarian stimulation in the same cycle (duostim) higher than with two consecutive antagonist cycles in poor responders? Based on the number of total and mature oocytes retrieved in women with poor ovarian response (POR), there is no benefit of duostim versus two consecutive antagonist cycles. Recent studies have shown the ability to obtain oocytes with equivalent quality from the follicular and the luteal phase, and a higher number of oocytes within one cycle when using duostim. If during follicular stimulation smaller follicles are sensitized and recruited, this may increase the number of follicles selected in the consecutive luteal phase stimulation, as shown in non-randomized controlled trials (RCT). This could be particularly relevant for women with POR. This is a multicentre, open-labelled RCT, performed in four IVF centres from September 2018 to March 2021. The primary outcome was the number of oocytes retrieved over the two cycles. The primary objective was to demonstrate in women with POR that two ovarian stimulations within the same cycle (first in the follicular phase, followed by a second in the luteal phase) led to the retrieval of 1.5 (2) more oocytes than the cumulative number of oocytes from two consecutive conventional stimulations with an antagonist protocol. In a superiority hypothesis, with power 0.8 alpha-risk 0.05 and a 35% cancellation rate, 44 patients were needed in each group. Patients were randomized by computer allocation. Eighty-eight women with POR, defined using adjusted Bologna criteria (antral follicle count ≤5 and/or anti-Müllerian hormone ≤1.2 ng/ml) were randomized, 44 in the duostim group and 44 in the conventional (control) group. HMG 300 IU/day with flexible antagonist protocol was used for ovarian stimulation, except in luteal phase stimulation of the duostim group. In the duostim group, oocytes were pooled and inseminated after the second retrieval, with a freeze-all protocol. Fresh transfers were performed in the control group, frozen embryo transfers were performed in both control and duostim groups in natural cycles. Data underwent intention-to-treat and per-protocol analyses. There was no difference between the groups regarding demographics, ovarian reserve markers, and stimulation parameters. The mean (SD) cumulative number of oocytes retrieved from two ovarian stimulations was not statistically different between the control and duostim groups, respectively, 4.6 (3.4) and 5.0 (3.4) [mean difference (MD) [95% CI] +0.4 [-1.1; 1.9], P = 0.56]. The mean cumulative numbersof mature oocytes and total embryos obtained were not significantly different between groups. The total number of embryos transferred by patient was significantly higher in the control group 1.5 (1.1) versus the duostim group 0.9 (1.1) (P = 0.03). After two cumulative cycles, 78% of women in the control group and 53.8% in the duostim group had at least one embryo transfer (P = 0.02). There was no statistical difference in the mean number of total and mature oocytes retrieved per cycle comparing Cycle 1 versus Cycle 2, both in control and duostim groups. The time to the second oocyte retrieval was significantly longer in controls, at 2.8 (1.3) months compared to 0.3 (0.5) months in the duostim group (P < 0.001). The implantation rate was similar between groups. The cumulative live birth rate was not statistically different, comparing controls versus the duostim group, 34.1% versus 17.9%, respectively (P = 0.08). The time to transfer resulting in an ongoing pregnancy did not differ in controls 1.7 (1.5) months versus the duostim group, 3.0 (1.6) (P = 0.08). No serious adverse events were reported. The RCT was impacted by the coronavirus disease 2019 pandemic and the halt in IVF activities for 10 weeks. Delays were recalculated to exclude this period; however, one woman in the duostim group could not have the luteal stimulation. We also faced unexpected good ovarian responses and pregnancies after the first oocyte retrieval in both groups, with a higher incidence in the control group. However, our hypothesis was based on 1.5 more oocytes in the luteal than the follicular phase in the duostim group, and the number of patients to treat was reached in this group (N = 28). This study was only powered for cumulative number of oocytes retrieved. This is the first RCT comparing the outcome of two consecutive cycles, either in the same menstrual cycle or in two consecutive menstrual cycles. In routine practice, the benefit of duostim in patients with POR regarding fresh embryo transfer is not confirmed in this RCT: first, because this study demonstrates no improvement in the number of oocytes retrieved in the luteal phase after follicular phase stimulation, in contrast to previous non-randomized studies, and second, because the freeze-all strategy avoids a pregnancy with fresh embryo transfer after the first cycle. However, duostim appears to be safe for women. In duostim, the two consecutive processes of freezing/thawing are mandatory and increase the risk of wastage of oocytes/embryos. The only benefit of duostim is to shorten the time to a second retrieval by 2 weeks if accumulation of oocytes/embryos is needed. This is an investigator-initiated study supported by a research Grant from IBSA Pharma. N.M. declares grants paid to their institution from MSD (Organon France); consulting fees from MSD (Organon France), Ferring, and Merck KGaA; honoraria from Merck KGaA, General Electrics, Genevrier (IBSA Pharma), and Theramex; support for travel and meetings from Theramex, Merck KGaG, and Gedeon Richter; and equipment paid to their institution from Goodlife Pharma. I.A. declares honoraria from GISKIT and support for travel and meetings from GISKIT. G.P.-B. declares Consulting fees from Ferring and Merck KGaA; honoraria from Theramex, Gedeon Richter, and Ferring; payment for expert testimony from Ferring, Merck KGaA, and Gedeon Richter; and support for travel and meetings from Ferring, Theramex, and Gedeon Richter. N.C. declares grants from IBSA pharma, Merck KGaA, Ferring, and Gedeon Richter; support for travel and meetings from IBSA pharma, Merck KGaG, MSD (Organon France), Gedeon Richter, and Theramex; and participation on advisory board from Merck KGaA. E.D. declares support for travel and meetings from IBSA pharma, Merck KGaG, MSD (Organon France), Ferring, Gedeon Richter, Theramex, and General Electrics. C.P.-V. declares support for travel and meetings from IBSA Pharma, Merck KGaA, Ferring, Gedeon Richter, and Theramex. M.Pi. declares support for travel and meetings from Ferring, Gedeon Richetr, and Merck KGaA. M.Pa. declares honoraria from Merck KGaA, Theramex, and Gedeon Richter; support for travel and meetings from Merck KGaA, IBSA Pharma, Theramex, Ferring, Gedeon Richter, and MSD (Organon France). H.B.-G. declares honoraria from Merck KGaA, and Gedeon Richter and support for travel and meetings from Ferring, Merck KGaA, IBSA Pharma, MSD (Organon France), Theramex, and Gedeon Richter. S.G. and M.B. have nothing to declare. Registration number EudraCT: 2017-003223-30. ClinicalTrials.gov identifier: NCT03803228. EudraCT: 28 July 2017. ClinicalTrials.gov: 14 January 2019. 3 September 2018.

Massin N ，Abdennebi I ，Porcu-Buisson G ，Chevalier N ，Descat E ，Piétin-Vialle C ，Goro S ，Brussieux M ，Pinto M ，Pasquier M ，Bry-Gauillard H ... -  《-》

Pretreatment with luteal estradiol for programming antagonist cycles compared to no pretreatment in advanced age women stimulated with corifollitropin alfa: a non-inferiority randomized controlled trial.

Does luteal estradiol (E2) pretreatment give a similar number of retrieved oocytes compared to no-pretreatment in advanced-aged women stimulated with corifollitropin alfa in an antagonist protocol? Programming antagonist cycles with luteal E2 gave similar number of retrieved oocytes compared to no-pretreatment in women aged 38-42 years. Programming antagonist cycles with luteal E2 pretreatment is a valuable tool to organize the IVF procedure better and is safe without any known impact on cycle outcome. However, variable effects were observed on the number of retrieved oocytes depending on the treated population. In advanced-age women, recruitable follicles tend to decrease in number and to be more heterogeneous in size but it remains unclear if estradiol pretreatment could change the oocyte yield through its negative feed-back effect on FSH intercycle rise. This non-blinded randomized controlled non-inferiority trial was conducted between 2016 and 2022 with centrally computerized randomization and concealed allocation. Participants were 324 women aged 38-42 years undergoing IVF treatment. The primary endpoint was the total number of retrieved oocytes. Statistical analysis was performed with one-sided alpha risk of 2.5% and 95% confidence interval (CI) with the non-inferiority of E2 pretreatment proved by a P value <0.025 and a lower delta margin of the CI within two oocytes compared to no pretreatment. Secondary endpoints were duration and total dosage of recombinant FSH, cancellation rate, percentage of oocyte pick-up (OPU) on working days, total number of metaphase II oocytes and obtained embryos, fresh transfer live birth rate, and cumulative live birth rate. This multicentric study enrolled women with regular cycles, weight >50 kg and body mass index <32, IVF cycle 1-2. According to randomization, micronized estradiol 2 mg twice a day was started on days 20-24 and continued until Wednesday beyond the onset of menses followed by administration of corifollitropin alfa on Friday, i.e. stimulation (S)1 or from D1-3 of a natural cycle in unpretreated patients. GnRH antagonist was started at S6 and additional FSH at S8. Basal characteristics were similar in patients randomized in E2 pretreated (n = 164) and non-pretreated (n = 160) groups (intended to treat (ITT) population). A total of 291 patients started treatment (per protocol (PP) population), 147 in E2 pretreated group with a mean number [SD] of pre-treatment days 9.8 [2.6] and 144 in the non-pretreated group. Despite advanced age, oocyte yields ranged from 0 to 29 in both groups with a median number of 6 retrieved oocytes in accordance with a mean anti-Müllerian hormone (AMH) level above 1.2 ng/ml. We demonstrated the non-inferiority of E2 pretreatment with a mean difference of -0.1 oocyte 95% CI [-1.5; 1.3] P = 0.004 in the PP population and a mean difference of -0.44 oocyte [-1.84; 0.97] P = 0.014 in the ITT population. Oocyte retrieval was more often on working days in E2 pretreated patients (91.9 versus 74.2%, P < 0.001). In patients reaching OPU, the duration of stimulation was statistically significantly longer (11.7 [1.7] versus 10.8 [1.8] days, P < 0.001) and the extra FSH dosage in addition to corifollitropin alfa was statistically significantly higher (1040 [548] versus 778 [504] IU, P < 0.001) in E2 pretreated than non-pretreated patients. We did not observe any significant differences in the number of retrieved oocytes (8.4 [6.1] versus 9.1 [6.0]), in the number of Metaphase 2 oocytes (7 [5.5] versus 7.3 [5.2]) nor in the number of obtained embryos (5 [4.6] versus 5.2 [4.2]) in E2 pretreated patients compared to non-pretreated patients. The live birth rate after fresh transfer (16.2% versus 18.5%, respectively), and the cumulative live birth rate per patient (17.7% versus 22.9%, respectively) were similar in both groups. Among the PP population, 31.6% of patients fulfilled the criteria for group 4 of Poseïdon classification (AMH <1.2 ng/ml and/or antral follicle count <5). In this sub-group of patients, we observed in contrast a statistically higher number of retrieved oocytes in E2 pretreated patients compared to non-pretreated (5.1 [3.8] versus 3.4 [2.7], respectively, the mean difference of +1.7 oocyte [0.2; 3.2] P = 0.022) but without significant difference in the cumulative live birth rate per patient (15.7% versus 7.3%, respectively). Our stimulated women older than 38 years obtained a wide range of collected oocytes suggesting very different stages of ovarian aging in both groups. E2 pretreatment is more likely to increase oocyte yield at the stage of ovarian aging characterized by asynchrony of a reduced follicular cohort. Another limitation is the sample size in sub-group analysis of patients with AMH <1.2 ng/ml. Finally, the absence of placebo for pretreatment could also introduce possible bias. Programming antagonist cycles with luteal E2 pretreatment seems a useful tool in advanced age women to better schedule oocyte retrievals on working days. However, the potential benefit of the number of collected oocytes remains to be demonstrated in a larger population displaying the characteristics of decreased ovarian reserve encountered in Poseïdon classification. Research grant from (MSD) Organon, France. I.C., S.D., B.B., X.M., S.G., and C.J. have no conflict of interest with this study. I.C.D. declares fees as speaker from Merck KGaA, Gedeon Richter, MSD (Organon, France), Ferring, Theramex, and IBSA and participation on advisory board from Merck KGaA. I.C.D. also declares consulting fees, and travel and meeting support from Merck KGaA. N.M. declares grants paid to their institution from MSD (Organon, France); consulting fees from MSD (Organon, France), Ferring, and Merck KGaA; honoraria from Merck KGaA, General Electrics, Genevrier (IBSA Pharma), and Theramex; support for travel and meetings from Theramex, Merck KGaG, and Gedeon Richter; and equipment paid to their institution from Goodlife Pharma. N.C. declares grants from IBSA Pharma, Merck KGaA, Ferring, and Gedeon Richter; support for travel and meetings from IBSA Pharma, Merck KGaG, MSD (Organon, France), Gedeon Richter, and Theramex; and participation on advisory board from Merck KGaA. A.G.L. declares fees as speaker from Merck KGaA, Gedeon Richter, MSD (Organon, France), Ferring, Theramex, and IBSA. ClinicalTrials.gov NCT02884245. 29 August 2016. 4 November 2016.

Cédrin-Durnerin I ，Carton I ，Massin N ，Chevalier N ，Dubourdieu S ，Bstandig B ，Michelson X ，Goro S ，Jung C ，Guivarc'h-Lévêque A ... -  《-》

The impact of luteal serum progesterone levels on live birth rates-a prospective study of 602 IVF/ICSI cycles.

Is the chance of a live birth following IVF treatment and fresh embryo transfer affected by early and mid-luteal serum progesterone (P4) levels? Low as well as high serum P4 levels in the early and mid-luteal phase reduce the chance of a live birth following IVF treatment with fresh embryo transfer. Data from non-human studies and studies of frozen-thawed embryo transfer cycles indicate that low as well as high P4 levels during the mid-luteal phase decrease the chance of pregnancy. The altered P4 pattern may disrupt the endometrial maturation leading to asynchrony between embryonic development and endometrial receptivity, thereby, compromising implantation and early development of pregnancy. Prospective multicenter cohort study of 602 women undergoing IVF treatment. Patients were recruited from four Danish public Fertility Centers from May 2014 to June 2017. The study population was unselected, thus, representing a normal everyday patient cohort. Patients were treated in a long GnRH-agonist protocol or a GnRH-antagonist protocol and triggered for final oocyte maturation with either hCG or a GnRH-agonist. The same vaginal luteal support regimen was applied in all patients. Serum P4 levels from the early or mid-luteal phase were correlated to positive hCG and live birth rates (delivery > gestational week 20). Patients were divided into four P4 groups based on raw data of P4 serum levels and reproductive outcomes during early luteal phase (P4<60 nmol/l, P4 60-100 nmol/l, P4 101-400 nmol/l and P4>400 nmol/l) and during mid-luteal phase (P4<150 nmol/l, P4 150-250 nmol/l, P4 251-400 nmol/l and P4>400 nmol/l). The optimal chance of pregnancy was achieved with serum P4 levels of 60-100 nmol/l in the early luteal phase whereas the optimal P4 level during the mid-luteal phase was 150-250 nmol/l. Below, but most distinctly above these levels, the chance of pregnancy was consistently reduced. With an early luteal P4 level of 60-100 nmol/l, the chance of a positive hCG-test was 73%, 95% CI: [59, 84] following cleavage stage embryo transfer. In contrast, with P4 levels >400 nmol/l, the chance of a positive hCG-test was significantly reduced to 35%, 95% CI: [17, 57], thus, an absolute risk difference of -38%, P = 0.01. A similar negative association between early luteal P4 and live birth rate was found, although it did not reach statistical significance. During the mid-luteal phase, a P4 level of 150-250 nmol/l resulted in an optimal chance of live birth: 54%, 95% CI: [37, 70] compared to 38%, 95% CI: [20, 60] with a P4 level >400 nmol/l, thus, an absolute risk difference of -16%, P = 0.14. All estimates were adjusted for maternal age, maternal BMI, study site, final follicle count and late follicular P4 levels. This study is the first to explore the possible upper and lower thresholds for luteal P4 following IVF treatment and fresh embryo transfer, and the optimal P4 ranges found in this study should be corroborated in future clinical trials. Furthermore, the P4 thresholds in this study only apply to fresh IVF cycles, using vaginal luteal phase support, as the optimal P4 level in cycles using intramuscular P4 may be different. Future studies are necessary to explore whether additional exogenous luteal P4 supplementation in the low P4 group could increase the chance of a live birth following fresh embryo transfer, and whether patients with luteal P4 levels >400 nmol/l would benefit from segmentation followed by subsequent transfer in frozen/thawed cycles. NCT02129998 (Clinicaltrials.gov). L.H.T. received an unrestricted grant from Ferring Pharmaceuticals, Denmark, to support this study. P.H. received unrestricted research grants from MSD, Merck, Gedeon Richter and Ferring Pharmaceuticals outside of this work as well as honoraria for lectures from MSD, Merck and Gedeon Richter outside of this work. U.K. received honoraria for lectures from MSD and Ferring Pharmaceuticals outside of this work. C.A. received unrestricted research grants from MSD, IBSA, and Ferring Pharmaceuticals outside of this work as well as honoraria for lectures from MSD and IBSA. H.O.E. and B.B.P. received an unrestricted research grant from Gedeon Richter outside of this work. K.E., L.B., D.P. and B.H. have no conflict of interest. Furthermore, grants from 'The Health Research Fund of Central Denmark Region', 'The Research Foundation of the Hospital of Central Jutland', 'The Research Foundation of A.P. Møller', 'The Research Foundation of Aase & Ejnar Danielsen', 'The Research Foundation of Dagmar Marshall', 'The Research Foundation of Dir. Jacob Madsen & Hustru Olga Madsen', 'The Research Foundation of Fam. Hede Nielsen' and 'The Danish Medical Research Grant' supported conducting this study. The providers of funding were neither involved in the conduction of the study nor in the writing of the scientific report.

Thomsen LH ，Kesmodel US ，Erb K ，Bungum L ，Pedersen D ，Hauge B ，Elbæk HO ，Povlsen BB ，Andersen CY ，Humaidan P ... -  《-》

Rectal progesterone administration secures a high ongoing pregnancy rate in a personalized Hormone Replacement Therapy Frozen Embryo Transfer (HRT-FET) protocol: a prospective interventional study.

Can supplementation with rectal administration of progesterone secure high ongoing pregnancy rates (OPRs) in patients with low serum progesterone (P4) on the day of blastocyst transfer (ET)? Rectally administered progesterone commencing on the ET day secures high OPRs in patients with serum P4 levels below 35 nmol/l (11 ng/ml). Low serum P4 levels at peri-implantation in Hormone Replacement Therapy Frozen Embryo Transfer (HRT-FET) cycles impact reproductive outcomes negatively. However, studies have shown that patients with low P4 after a standard vaginal progesterone treatment can obtain live birth rates (LBRs) comparable to patients with optimal P4 levels if they receive additionalsubcutaneous progesterone, starting around the day of blastocyst transfer. In contrast, increasing vaginal progesterone supplementation in low serum P4 patients does not increase LBR. Another route of administration rarely used in ART is the rectal route, despite the fact that progesterone is well absorbed and serum P4 levels reach a maximum level after ∼2 h. This prospective interventional study included a cohort of 488 HRT-FET cycles, in which a total of 374 patients had serum P4 levels ≥35 nmol/l (11 ng/ml) at ET, and 114 patients had serum P4 levels <35 nmol/l (11 ng/ml). The study was conducted from January 2020 to November 2022. Patients underwent HRT-FET in a public Fertility Clinic, and endometrial preparation included oral oestradiol (6 mg/24 h), followed by vaginal micronized progesterone, 400 mg/12 h. Blastocyst transfer and P4 measurements were performed on the sixth day of progesterone administration. In patients with serum P4 <35 nmol/l (11 ng/ml), 'rescue' was performed by rectal administration of progesterone (400 mg/12 h) starting that same day. In pregnant patients, rectal administration continued until Week 8 of gestation, and oestradiol and vaginal progesterone treatment continued until Week 10 of gestation. Among 488 HRT-FET single blastocyst transfers, the mean age of the patients at oocyte retrieval (OR) was 30.9 ± 4.6 years and the mean BMI at ET 25.1 ± 3.5 kg/m2. The mean serum P4 level after vaginal progesterone administration on the day of ET was 48.9 ± 21.0 nmol/l (15.4 ± 6.6 ng/ml), and a total of 23% (114/488) of the patients had a serum P4 level lower than 35 nmol/l (11 ng/ml). The overall, positive hCG rate, clinical pregnancy rate, OPR week 12, and total pregnancy loss rate were 66% (320/488), 54% (265/488), 45% (221/488), and 31% (99/320), respectively. There was no significant difference in either OPR week 12 or total pregnancy loss rate between patients with P4 ≥35 nmol/l (11 ng/ml) and patients with P4 <35 nmol/l, who received rescue in terms of rectally administered progesterone, 45% versus 46%, P = 0.77 and 30% versus 34%, P = 0.53, respectively. OPR did not differ whether patients had initially low P4 and rectal rescue or were above the P4 cut-off. Logistic regression analysis showed that only age at OR and blastocyst scoring correlated with OPR week 12, independently of other factors like BMI and vitrification day of blastocysts (Day 5 or 6). In this study, vaginal micronized progesterone pessaries, a solid pessary with progesterone suspended in vegetable hard fat, were used vaginally as well as rectally. It is unknown whether other vaginal progesterone products, such as capsules, gel, or tablet, could be used rectally with the same rescue effect. A substantial part of HRT-FET patients receiving vaginal progesterone treatment has lowserum P4. Adding rectally administered progesterone in these patients increases the reproductive outcome. Importantly, rectal progesterone administration is considered convenient, and progesterone pessaries are easy to administer rectally and of low cost. Gedeon Richter Nordic supported the study with an unrestricted grant as well as study medication. B.A. has received unrestricted grant from Gedeon Richter Nordic and Merck and honoraria for lectures from Gedeon Richter, Merck, IBSA and Marckyrl Pharma. P.H. has received honoraria for lectures from Gedeon Richter, Merck, IBSA and U.S.K. has received grant from Gedeon Richter Nordic, IBSA and Merck for studies outside this work and honoraria for teaching from Merck and Thillotts Pharma AB and conference expenses covered by Merck. The other co-authors have no conflict of interest to declare. EudraCT no.: 2019-001539-29.

Alsbjerg B ，Jensen MB ，Povlsen BB ，Elbaek HO ，Laursen RJ ，Kesmodel US ，Humaidan P ... -  《-》