Subcutaneous luteal phase progesterone rescue rectifies ongoing pregnancy rates in hormone replacement therapy vitrified-warmed blastocyst transfer cycles

Natural proliferative phase frozen embryo transfer-a new approach which may facilitate scheduling without hindering pregnancy outcomes

STUDY QUESTION

How does a natural proliferative phase (NPP) strategy for frozen embryo transfer (FET) compare with the conventional artificial (AC) and natural (NC) endometrial preparation protocols in terms of live birth rates (LBR)?

SUMMARY ANSWER

This study supports the hypothesis that, just as for NC, NPP-FET may be a superior alternative to AC in terms of LBR.

WHAT IS KNOWN ALREADY

Although FETs are increasing worldwide, the optimal FET protocol is still largely controversial. Despite recent evidence supporting a possibly higher efficacy and safety of NC FETs, their widespread use is limited by the difficulties encountered during cycle monitoring and scheduling.

STUDY DESIGN, SIZE, DURATION

In this single center retrospective cohort study, we describe the NPP-FET protocol, in which vaginal progesterone is initiated during the proliferative phase as soon as an endometrium with a thickness of at least 7 mm is identified and ovulation is ruled out, regardless of mean diameter of the dominant follicle.

PARTICIPANTS/MATERIALS, SETTING, METHODS

For comparison, we considered all blastocyst stage FET cycles preformed at a private infertility center between January 2010 and June 2022, subdivided according to the following subgroups of endometrial preparation: AC, NPP, and NC. We performed multivariable generalized estimating equations regression analysis to account for the following potential confounding variables: oocyte age at retrieval, oocyte source (autologous without preimplantation genetic testing for aneuploidies (PGT-A) versus autologous with PGT-A versus donated), number of oocytes retrieved/donated, embryo developmental stage (Day 5 versus Day 6), number of embryos transferred, quality of the best embryo transferred, and year of treatment. The main outcome measure was LBR. The secondary outcomes included hCG positive, clinical pregnancy and miscarriage rates, and the following perinatal outcomes: first trimester bleeding, second/third trimester bleeding, preterm rupture of membranes, gestational diabetes, gestational hypertensive disorders (GHD), and gestational age at delivery.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 5791 FET cycles were included in this analysis (2226 AC, 349 NPP, and 3216 NC). The LBR for FET was lower in the AC subgroup when compared to the NPP and NC (38.4%, 49.1%, and 45.2%, respectively; P < 0.01 AC versus NPP and AC versus NC). The rates of miscarriage were also lower in the NPP and NC subgroups when compared to AC (19.7%, 25.0%, and 34.9%, respectively; P < 0.01 NPP versus AC and NC versus AC). Considering perinatal outcomes, NPP-FET and NC were associated with a significantly lower first trimester bleeding compared to AC (17.3%, 14.7%, and 37.6%, respectively; P < 0.01 NPP versus AC and NC versus AC). Additionally, NC was associated with a lower rate of GHD when compared with AC (8.6% versus 14.5%, P < 0.01), while the rate following NPP-FET was 9.4%.

LIMITATIONS, REASONS FOR CAUTION

This study is limited by its retrospective design. Moreover, there was also a low number of patients in the NPP subgroup, which may have led the study to be underpowered to detect clinically relevant differences between the subgroups.

WIDER IMPLICATIONS OF THE FINDINGS

Our study posits that the NPP-FET protocol may be an effective and safe alternative to both NC and AC, while still allowing for enhanced practicality in patient follow-up and FET scheduling. Further investigation on NPP-FET is warranted, with prospective studies including a larger and more homogeneous subsets of patients.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the IVI-RMA-Lisbon (2008-LIS-053-CG). The authors did not receive any funding for this study. The authors have no competing interests.

TRIAL REGISTRATION NUMBER

Not applicable.

Luteal phase support in assisted reproductive technology centers: Italian survey

BACKGROUND

In assisted reproductive cycles (ART), the fine balance of controlling corpus luteum function is severely disrupted. To challenge this iatrogenic deficiency, clinicians aim to provide exogenous support. Several reviews have investigated progesterone route of administration, dosage and timing.

METHODS

A survey about luteal phase support (LPS) after ovarian stimulation was conducted among doctors in charge in Italian II-III level ART centers.

RESULTS

With regards to the general approach to LPS, 87.9% doctors declare to diversify the approach; the reasons for diversifying (69.7%) were based on the type of cycle. For all the most important administration routes (vaginal, intramuscular, subcutaneous) it appears that in frozen cycles there is a shift towards higher dosages. The 90.9% of the centers use vaginal progesterone, and when a combined approach is required, in 72.7% of cases vaginal administration is combined with injective route of administration. When Italian doctors were asked about the beginning and duration of LPS, 96% of the centers start the day of the pickup or the day after, while 80% of the centers continue LPS until week 8-12. The rate of participation of the centers confirms the low perceived importance of LPS among Italian ART centers, while may be considered quite surprising the relatively higher percentage of centers that measures P level. Tailorization to women's needs is the new objective of LPS: self-administration, good tolerability are the main aspects for Italian centers.

CONCLUSIONS

In conclusion, results of Italian survey are consistent to results of main international surveys about LPS.

A model for predicting low progesterone levels on the day of embryo transfer in hormonally prepared vitrified-warmed embryo transfer cycles: A secondary analysis of a prospective cohort study

AIM

To develop a model that predicts low progesterone (P) levels on the day of embryo transfer (ET) based on patient and cycle characteristics, including serum estradiol (E2 ) concentration after vaginal administration of micronized E2 for endometrial preparation.

METHODS

A prospective cohort of 193 patients scheduled for cryopreserved blastocyst transfer during an artificial endometrial preparation cycle, using micronized E2 vaginally for first 4 days (4 mg/day), followed by oral administration (6 mg/day). Blood sampling for E2 was performed prospectively on day-5 of vaginal administration and analysis was performed retrospectively. On sixth day of P treatment (daily 300 mg of vaginal micronized P tablets), P levels were measured on ET day. Primary outcome measure was serum P levels after vaginal E2 administration.

RESULTS

Patients with low P levels on the day of ET (<7.8 ng/mL, 25th percentile) were heavier (p < 0.001) and exhibited lower day 5 serum E2 levels (p < 0.001) compared with patients with adequate P levels. Multivariate linear regression analysis revealed that weight (p = 0.003) and day 5 E2 levels (p < 0.001) were independently associated with the P levels. The sensitivity, specificity, and positive and negative predictive values (%) were 71.4, 55.6, 35.4, and 85.1 for weight ≥ 65 kg; 71.4, 61.8, 38.9, and 86.4 for day 5 E2  ≤ 1615 pg/mL; 59.2, 83.3, 54.7, and 85.7 for the combination of these two variables; and 82.9, 62.5, 54.7, and 87.0 for the sequential inclusion of these variables, respectively.

CONCLUSIONS

Low day 5 E2 levels following vaginal administration and high weight are independently associated with low P levels on the day of ET. Predictive performance is enhanced when these variables are considered sequentially or in combination.

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

STUDY QUESTION

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)?

SUMMARY ANSWER

Rectally administered progesterone commencing on the ET day secures high OPRs in patients with serum P4 levels below 35 nmol/l (11 ng/ml).

WHAT IS KNOWN ALREADY

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.

STUDY DESIGN, SIZE, DURATION

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.

PARTICIPANTS/MATERIALS, SETTING, METHODS

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.

MAIN RESULTS AND THE ROLE OF CHANCE

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).

LIMITATIONS, REASONS FOR CAUTION

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.

WIDER IMPLICATIONS OF THE FINDINGS

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.

STUDY FUNDING/COMPETING INTEREST(S)

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.

TRIAL REGISTRATION NUMBER (25)

EudraCT no.: 2019-001539-29.

Association of serum progesterone levels on the transfer day with pregnancy outcomes in hormone replacement frozen-thawed cycles with oral dydrogesterone for strengthened luteal phase support

OBJECTIVE

To investigate the relationship between serum progesterone (P) levels on the day of blastocyst transfer and pregnancy outcomes in frozen-thawed embryo transfer (FET) cycles using hormone replacement therapy (HRT) with oral dydrogesterone for strengthened luteal phase support (LPS).

MATERIALS AND METHODS

This was a retrospective study including 1176 FET cycles. All patients received 40 mg of intramuscular (IM) P daily for endometrium transformation plus oral dydrogesterone 10 mg BID from transfer day for strengthened LPS. Pregnancy outcomes were compared between serum P levels on the transfer day ≥10 ng/ml and <10 ng/ml. Furthermore, cycles were divided into 10 groups by deciles of P and ongoing pregnancy rate (OPR) was calculated in each group. Analyses using deciles of serum P were completed to see if these could create further prognostic power.

RESULTS

No differences were observed in clinical pregnancy rates (CPRs), OPRs and live birth rates (LBRs) between serum P levels ≥10 ng/ml and <10 ng/ml. Patients with serum P levels <5.65 ng/ml (10th percentile) had a significantly lower OPR (48.31% vs. 58.98%, p = 0.03) and LBR (43.22% vs. 57.75%, p = 0.003) than the rest of the patients. Multivariate logistic regression analysis showed serum P levels on the transfer day were not associated with pregnancy outcomes.

CONCLUSION

Measuring serum P levels on the day of HRT-FET is of clinical importance. Lower serum P levels impact the success of HRT-FET cycles, suggesting that there may be a threshold below which it is difficult to improve pregnancy outcomes via oral dydrogesterone to strengthen LPS.

Comparison of the efficacy of subcutaneous versus vaginal progesterone using a rescue protocol in vitrified blastocyst transfer cycles

RESEARCH QUESTION

Does administration of subcutaneous (s.c.) progesterone support ongoing pregnancy rates (OPR) similar to vaginal progesterone using a rescue protocol in hormone replacement therapy frozen embryo transfer cycles?

DESIGN

Retrospective cohort study. Two sequential cohorts - vaginal progesterone gel (December 2019-October 2021; n=474) and s.c. progesterone (November 2021-November 2022; n=249) -were compared. Following oestrogen priming, s.c. progesterone 25 mg twice daily (b.d.) or vaginal progesterone gel 90 mg b.d. was administered. Serum progesterone was measured 1 day prior to warmed blastocyst transfer (i.e. day 5 of progesterone administration). In patients with serum progesterone concentrations <8.75 ng/ml, additional s.c. progesterone (rescue protocol; 25 mg) was provided.

RESULTS

In the vaginal progesterone gel group, 15.8% of patients had serum progesterone <8.75 ng/ml and received the rescue protocol, whereas no patients in the s.c. progesterone group received the rescue protocol. OPR, along with positive pregnancy and clinical pregnancy rates, were comparable between the s.c. progesterone group without the rescue protocol and the vaginal progesterone gel group with the rescue protocol. After the rescue protocol, the route of progesterone administration was not a significant predictor of ongoing pregnancy. The impact of different serum progesterone concentrations on reproductive outcomes was evaluated by percentile (<10th, 10-49th, 50-90th and >90th percentiles), taking the >90th percentile as the reference subgroup. In both the vaginal progesterone gel group and the s.c. progesterone group, all serum progesterone percentile subgroups had similar OPR.

CONCLUSIONS

Subcutaneous progesterone 25 mg b.d. secures serum progesterone >8.75 ng/ml, whereas additional exogenous progesterone (rescue protocol) was needed in 15.8% of patients who received vaginal progesterone. The s.c. and vaginal progesterone routes, with the rescue protocol if needed, yield comparable OPR.

Effectiveness of progesterone rescue in women presenting low circulating progesterone levels around the day of embryo transfer: a systematic review and meta-analysis

IMPORTANCE

Over the last decade, frozen embryo transfer (FET) has been increasingly used in contemporary fertility units. Despite the rapid increase in FET, there is still insufficient evidence to recommend an optimized protocol for endometrial preparation especially in patients with lower progesterone (P4) levels. Previous studies have concluded that P4 levels <10 ng/mL are associated with poorer pregnancy outcomes than those reported with high levels of circulating P4.

OBJECTIVE

To identify whether rescue P4 dosing in patients with low P4 can salvage adverse outcomes associated with low P4 levels, resulting in outcomes comparable to patients with adequate progesterone.

DATA SOURCES

The study was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-analyses guidelines and prospectively registered under the PROSPERO database (CRD42022357125). Six databases (Embase, MEDLINE, APA PsycInfo, Global Health, HMIC Health Management Information Consortium, and Google Scholar) and 2 additional sources were searched from inception to August 29, 2022.

STUDY SELECTION AND SYNTHESIS

Prospective and retrospective cohort studies, reporting the association between rescue progesterone and one or more pregnancy outcomes, were included. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS), while the quality of evidence by the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework. Summative and subgroup data as well as heterogeneity were generated by the Cochrane platform RevMan (V. 5.4).

MAIN OUTCOME MEASURE(S)

To compare ongoing pregnancy rate as primary outcome and clinical pregnancy rate, miscarriage rate, and live birth rate as secondary outcomes between patients with low (<10 ng/mL) receiving rescue progesterone vs. those with adequate levels of P4 (≥10 ng/mL).

RESULT(S)

Overall, 7 observational studies were included in the analysis, with a total of 5927 patients of median age 34 (interquartile range [IQR]: 31.55, 37.13). Overall, patient group comparison, namely those with low P4 that received a rescue dose and those with adequate P4 levels, did not yield significant differences for either the primary or secondary outcomes. For ongoing clinical pregnancy, patients with low P4 receiving the rescue dose vs. those with adequate P4 levels was odds ratio (OR) 0.98 (95% CI: 0.78, 1.24; P = .86, I²: 41%), whereas for miscarriage events, OR was 0.98 (95% CI: 0.81, 1.17; P = .80, I²: 0). Equally, for clinical pregnancy, OR was 0.91 (95% CI: 0.78, 1.06; P = .24; I²: 33%), and for live birth, OR was 0.92 (95% CI: 0.77, 1.09; P = .33; I²: 43%). Subgroup analysis on the basis or rescue administration route successfully explained summative heterogeneity.

CONCLUSION(S)

Rescue P4 dosing in patients with low P4 results in ongoing pregnancy rate, clinical pregnancy and live birth rates were comparable to those of patients with adequate P4 levels. However, robust randomized controlled trials assessing rescue treatment in women with low P4 are needed to confirm these findings. Rescue P4 in patients with low circulating P4 around embryo transfer day may result in reproductive outcomes comparable to those with adequate P4 levels.

STUDY REGISTRATION

CRD42022357125 (PROSPERO).

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

STUDY QUESTION

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)?

SUMMARY ANSWER

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.

WHAT IS KNOWN ALREADY

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.

STUDY DESIGN, SIZE, DURATION

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.

PARTICIPANTS/MATERIALS, SETTING, METHODS

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.

MAIN RESULTS AND THE ROLE OF CHANCE

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.

LIMITATIONS, REASONS FOR CAUTION

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.

WIDER IMPLICATIONS OF THE FINDINGS

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.

STUDY FUNDING/COMPETING INTEREST(S)

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.

TRIAL REGISTRATION NUMBER

The study was registered at clinical trials.gov (NCT04128436).

Endometriosis patients benefit from high serum progesterone in hormone replacement therapy-frozen embryo transfer cycles: a cohort study

RESEARCH QUESTION

What is the optimal serum progesterone cut-off level in patients with endometriosis undergoing hormone replacement therapy frozen embryo transfer (HRT-FET) with intensive progesterone luteal phase support?

DESIGN

A cohort study, including 262 HRT-FET cycles in 179 patients all diagnosed with endometriosis either by laparoscopy or by ultrasound in patients with visible endometriomas. Pre-treatment consisted of 42 days of oral contraceptive pills and 5 days' wash-out, followed by 6 mg oral oestrogen daily. Exogenous progesterone supplementation with vaginal progesterone gel 90 mg/12h commenced when the endometrium was 7 mm or thicker. From the fourth day of vaginal progesterone supplementation, patients also received intramuscular progesterone 50 mg daily. Blastocyst transfer was scheduled for the sixth day of progesterone supplementation.

RESULTS

The overall positive HCG, live birth (LBR) and total pregnancy loss rates were 60%, 39% and 34%, respectively. The optimal progesterone cut-off level was 118 nmol/l (37.1 ng/ml) defined as the maximum of the Youden index. The unadjusted LBR was significantly higher in patients with progesterone measuring 118 nmol/l or above compared with patients with progesterone measuring less than 118 nmol/l (51% [44/86] versus 34% [59/176], P = 0.01), whereas the adjusted odds ratio for a live birth was 2.1 (95% CI 1.2 to 3.7) after adjusting for age, body mass index, blastocyst score, blastocyst age, quality and number of blastocysts transferred.

CONCLUSIONS

Serum progesterone levels above 118 nmol/l (37.1ng/ml) resulted in significantly higher LBR compared with lower serum progesterone levels, suggesting that a threshold for optimal serum progesterone exists.

The effect of frozen embryo transfer regimen on the association between serum progesterone and live birth: a multicentre prospective cohort study (ProFET)

STUDY QUESTION

What is the association between serum progesterone levels on the day of frozen embryo transfer (FET) and the probability of live birth in women undergoing different FET regimens?

SUMMARY ANSWER

Overall, serum progesterone levels <7.8 ng/ml were associated with reduced odds of live birth, although the association between serum progesterone levels and the probability of live birth appeared to vary according to the route of progesterone administration.

WHAT IS KNOWN ALREADY

Progesterone is essential for pregnancy success. A recent systematic review showed that in FET cycles using vaginal progesterone for endometrial preparation, lower serum progesterone levels (<10 ng/ml) were associated with a reduction in live birth rates and higher chance of miscarriage. However, there was uncertainty about the association between serum progesterone levels and treatment outcomes in natural cycle FET (NC-FET) and HRT-FET using non-vaginal routes of progesterone administration.

STUDY DESIGN SIZE DURATION

This was a multicentre (n = 8) prospective cohort study conducted in the UK between January 2020 and February 2021.

PARTICIPANTS/MATERIALS SETTING METHODS

We included women having NC-FET or HRT-FET treatment with progesterone administration by any available route. Women underwent venepuncture on the day of embryo transfer. Participants and clinical personnel were blinded to the serum progesterone levels. We conducted unadjusted and multivariable logistic regression analyses to investigate the association between serum progesterone levels on the day of FET and treatment outcomes according to the type of cycle and route of exogenous progesterone administration. Our primary outcome was the live birth rate per participant.

MAIN RESULTS AND THE ROLE OF CHANCE

We studied a total of 402 women. The mean (SD) serum progesterone level was 14.9 (7.5) ng/ml. Overall, the mean adjusted probability of live birth increased non-linearly from 37.6% (95% CI 26.3-48.9%) to 45.5% (95% CI 32.1-58.9%) as serum progesterone rose between the 10th (7.8 ng/ml) and 90th (24.0 ng/ml) centiles. In comparison to participants whose serum progesterone level was ≥7.8 ng/ml, those with lower progesterone (<7.8 ng/ml, 10th centile) experienced fewer live births (28.2% versus 40.0%, adjusted odds ratio [aOR] 0.41, 95% CI 0.18-0.91, P = 0.028), lower odds of clinical pregnancy (30.8% versus 45.1%, aOR 0.36, 95% CI 0.16-0.79, P = 0.011) and a trend towards increased odds of miscarriage (42.1% versus 28.7%, aOR 2.58, 95% CI 0.88-7.62, P = 0.086). In women receiving vaginal progesterone, the mean adjusted probability of live birth increased as serum progesterone levels rose, whereas women having exclusively subcutaneous progesterone experienced a reduction in the mean probability of live birth as progesterone levels rose beyond 16.3 ng/ml. The combination of vaginal and subcutaneous routes appeared to exert little impact upon the mean probability of live birth in relation to serum progesterone levels.

LIMITATIONS REASONS FOR CAUTION

The final sample size was smaller than originally planned, although our study was adequately powered to confidently identify a difference in live birth between optimal and inadequate progesterone levels. Furthermore, our cohort did not include women receiving oral or rectal progestogens.

WIDER IMPLICATIONS OF THE FINDINGS

Our results corroborate existing evidence suggesting that lower serum progesterone levels hinder FET success. However, the relationship between serum progesterone and the probability of live birth appears to be non-linear in women receiving exclusively subcutaneous progesterone, suggesting that in this subgroup of women, high serum progesterone may also be detrimental to treatment success.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by CARE Fertility and a doctoral research fellowship (awarded to P.M.) by the Tommy's Charity and the University of Birmingham. M.J.P. is supported by the NIHR Birmingham Biomedical Research Centre. S.F. is a minor shareholder of CARE Fertility but has no financial or other interest with progesterone testing or manufacturing companies. P.L. reports personal fees from Pharmasure, outside the submitted work. G.P. reports personal fees from Besins Healthcare, outside the submitted work. M.W. reports personal fees from Ferring Pharmaceuticals, outside the submitted work. The remaining authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT04170517.

Effectiveness of progesterone supplementation in women presenting low progesterone levels on the day of frozen embryo transfer: a randomised controlled trial

INTRODUCTION

Progesterone is an essential hormone involved in the process of implantation and pregnancy maintenance. Evidence from recent studies has supported the importance of serum progesterone level around the time of embryo transfer in hormonal replacement therapy frozen embryo transfer cycles and recommended the need for individualised luteal support. Low progesterone around the time of embryo transfer is found to be associated with decreased rate of pregnancy after frozen embryo transfer. This single-centre, longitudinal, randomised, interventional controlled study aims to compare the rate of ongoing pregnancy between two groups of women with progesterone level below 10 ng/mL on the day of frozen embryo transfer: the study group using 800 mg vaginal micronised progesterone supplemented with 50 mg intramuscular progesterone per day and the control group using only 800 mg vaginal micronised progesterone.

METHODS AND ANALYSIS

We enrol patients who are undergoing frozen embryo transfers with blastocyst-stage or cleavage-stage embryos and who satisfy the inclusion and exclusion criteria. After signing the informed consent, participants are randomised into two groups: the study group using vaginal micronised progesterone supplemented with progesterone intramuscular 50 mg per day and the control group using only vaginal micronised progesterone. Randomisation will be performed using R software at a 1:1 allocation ratio. Sequentially numbered, opaque sealed envelopes are used for allocation. The primary outcome is the rate of ongoing pregnancy. To demonstrate a difference of 10% with regard to rate of ongoing pregnancy, at least 370 participants per arm are required (type I error α=0.05, power=0.8). Assuming a dropout rate of 10%, a total of 824 patients (412 per group) will be invited.

ETHICS AND DISSEMINATION

This study was approved by the Ethics Committee of Tu Du Hospital on 17 May 2021 (reference number: 1251/QĐ-BVTD). All participants provide informed consent before being enrolled in the study. The results of our study will be submitted to reproductive medicine conferences and journals.

TRIAL REGISTRATION NUMBER

NCT04897269.

Low Luteal Serum Progesterone Levels Are Associated With Lower Ongoing Pregnancy and Live Birth Rates in ART: Systematic Review and Meta-Analyses

Progesterone plays a key role in implantation. Several studies reported that lower luteal progesterone levels might be related to decreased chances of pregnancy. This systematic review was conducted using appropriate key words, on MEDLINE, EMBASE, and the Cochrane Library, from 1990 up to March 2021 to assess if luteal serum progesterone levels are associated with ongoing pregnancy (OP) and live birth (LB) rates (primary outcomes) and miscarriage rate (secondary outcome), according to the number of corpora lutea (CLs). Overall 2,632 non-duplicate records were identified, of which 32 relevant studies were available for quantitative analysis. In artificial cycles with no CL, OP and LB rates were significantly decreased when the luteal progesterone level falls below a certain threshold (risk ratio [RR] 0.72; 95% confidence interval [CI] 0.62-0.84 and 0.73; 95% CI 0.59-0.90, respectively), while the miscarriage rate was increased (RR 1.48; 95% CI 1.17-1.86). In stimulated cycles with several CLs, the mean luteal progesterone level in the no OP and no LB groups was significantly lower than in the OP and LB groups [difference in means 68.8 (95% CI 45.6-92.0) and 272.4 (95% CI 10.8-533.9), ng/ml, respectively]. Monitoring luteal serum progesterone levels could help in individualizing progesterone administration to enhance OP and LB rates, especially in cycles without corpus luteum.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=139019, identifier 139019.

Individualized luteal phase support based on serum progesterone levels in frozen-thawed embryo transfer cycles maximizes reproductive outcomes in a cohort undergoing preimplantation genetic testing

INTRODUCTION

Low serum progesterone concentration on frozen embryo transfer (FET) day in hormone replacement therapy (HRT) cycles results in lower reproductive outcomes. Recent studies showed the efficiency of a "rescue protocol'' to restore reproductive outcomes in these patients. Here, we compared reproductive outcomes in HRT FET cycles in women with low serum progesterone levels who received individualized luteal phase support (iLPS) and in women with adequate serum progesterone levels who underwent in vitro fertilization for pre-implantation genetic testing for structural rearrangements or monogenic disorders.

DESIGN

This retrospective cohort study included women (18-43 years of age) undergoing HRT FET cycles with pre-implantation genetic testing at Montpellier University Hospital between June 2020 and May 2022. A standard HRT was used: vaginal micronized estradiol (6mg/day) followed by vaginal micronized progesterone (VMP; 800 mg/day). Serum progesterone was measured after four doses of VMP: if <11ng/ml, 25mg/day subcutaneous progesterone or 30mg/day oral dydrogesterone was introduced.

RESULTS

125 HRT FET cycles were performed in 111 patients. Oral/subcutaneous progesterone supplementation concerned 39 cycles (n=20 with subcutaneous progesterone and n=19 with oral dydrogesterone). Clinical and laboratory parameters of the cycles were comparable between groups. The ongoing pregnancy rate (OPR) was 41.03% in the supplemented group and 18.60% in the non-supplemented group (p= 0.008). The biochemical pregnancy rate and miscarriages rate tended to be higher in the non-supplemented group versus the supplemented group: 13.95% versus 5.13% and 38.46% versus 15.79% (p=0.147 and 0.182 respectively). Multivariate logistic regression analysis found that progesterone supplementation was significantly associated with higher OPR ​​ (adjusted OR = 3.25, 95% CI [1.38 - 7.68], p=0.007).

CONCLUSION

In HRT FET cycles, progesterone supplementation in patients with serum progesterone concentration <11 ng/mL after four doses of VMP significantly increases the OPR.

Implantation Failures and Miscarriages in Frozen Embryo Transfers Timed in Hormone Replacement Cycles (HRT): A Narrative Review

The recent advent of embryo vitrification and its remarkable efficacy has focused interest on the quality of hormone administration for priming frozen embryo transfers (FETs). Products available for progesterone administration have only been tested in fresh assisted reproduction technologies (ARTs) and not in FET. Recently, there have been numerous concordant reports pointing at the inefficacy of vaginal preparations at delivering sufficient progesterone levels in a sizable fraction of FET patients. The options available for coping with these shortcomings of vaginal progesterone include (i) rescue options with the addition of injectable subcutaneous (SC) progesterone at the dose of 25 mg/day administered either solely to women whose circulating progesterone is <10 ng/mL or to all in a combo option and (ii) the exclusive administration of SC progesterone at the dose of 25 mg BID. The wider use of segmented ART accompanied with FET forces hormone replacement regimens used for priming endometrial receptivity to be adjusted in order to optimize ART outcomes.

Individualized luteal phase support normalizes live birth rate in women with low progesterone levels on the day of embryo transfer in artificial endometrial preparation cycles

OBJECTIVE

To analyze the impact on live birth rates (LBRs) of the individualized luteal phase support (termed iLPS) in patients with low serum progesterone (P) levels compared with patients without iLPS.

DESIGN

Retrospective cohort study, December 1, 2018, to May 30, 2019.

SETTING

Private medical center.

PATIENT(S)

A total of 2,275 patients checked for serum P on the day of blastocyst transfer were analyzed. During the study period, 1,299 patients showed serum P levels of ≥9.2 ng/mL, whereas 550 showed serum P levels of <9.2 ng/mL and received iLPS. Additionally, a historical group of 426 patients with serum P levels of <9.2 ng/mL but no iLPS were used for comparison. Eligible patients were aged ≤50 years with adequate endometrium morphology after receiving estrogens. Luteal phase support was provided with micronized vaginal P (MVP) to all women. Patients with personalized initiation of exogenous P according to the endometrial receptivity assay test, polyps, fibroids distorting the cavity, or hydrosalpinx were not included in the analysis.

INTERVENTION(S)

As routine practice since December 2018, patients with low serum P levels received an iLPS with a daily injection of 25 mg of subcutaneous P from the day of embryo transfer (ET) in addition to standard LPS (400 mg of MVP twice a day).

MAIN OUTCOME MEASURE(S)

Live birth rate.

RESULT(S)

The LBR was 44.9% in the iLPS cases vs. 45.0% in patients with normal serum P levels (crude odds ratio [OR], 1.0; 95% confidence interval [CI], 0.82-1.22). By regression analysis, low serum P levels did not affect the LBR after adjusting for possible confounders (age, oocyte origin, fresh vs. frozen, day of ET, embryo quality, number of embryos transferred) (adjusted OR, 0.99; 95% CI, 0.79-1.25). Similarly, no differences were observed in other pregnancy outcomes between groups. The LBR was significantly higher in the group of patients who received additional subcutaneous P (iLPS) compared with the historical group with low serum P levels and no iLPS (44.9% vs. 37.3%; OR, 1.37; 95% CI, 1.06-1.78). In the overall population, patients showing P levels of <9.2 ng/mL on the day of ET were slightly younger and had higher body mass index and lower estradiol and P levels during the proliferative phase compared with patients with P levels of ≥9.2 ng/mL. No differences were observed with regard to the time in between the last dose of MVP and the serum P determination. After a multivariable logistic regression analysis, only body mass index and estradiol levels in the proliferative phase reminded statistically significant. Significant differences in the LBR were observed between patients with serum P levels of <9.2 ng/mL without iLPS and patients with serum P levels of ≥9.2 ng/mL when using either own or donated oocytes.

CONCLUSION(S)

Individualized LPS for patients with low serum P levels produces LBRs similar to those of patients with adequate serum P levels.

Preparation of the Endometrium for Frozen Embryo Transfer: A Systematic Review

Despite the worldwide increase in frozen embryo transfer, the search for the best protocol to prime endometrium continues. Well-designed trials comparing various frozen embryo transfer protocols in terms of live birth rates, maternal, obstetric and neonatal outcome are urgently required. Currently, low-quality evidence indicates that, natural cycle, either true natural cycle or modified natural cycle, is superior to hormone replacement treatment protocol. Regarding warmed blastocyst transfer and frozen embryo transfer timing, the evidence suggests the 6th day of progesterone start, LH surge+6 day and hCG+7 day in hormone replacement treatment, true natural cycle and modified natural cycle protocols, respectively. Time corrections, due to inter-personal differences in the window of implantation or day of vitrification (day 5 or 6), should be explored further. Recently available evidence clearly indicates that, in hormone replacement treatment and natural cycles, there might be marked inter-personal variation in serum progesterone levels with an impact on reproductive outcomes, despite the use of the same dose and route of progesterone administration. The place of progesterone rescue protocols in patients with low serum progesterone levels one day prior to warmed blastocyst transfer in hormone replacement treatment and natural cycles is likely to be intensively explored in near future.