Evaluation of progestogen supplementation for luteal phase support in fresh in vitro fertilization cycles

The Impact of Progesterone Administration Routes on Endometrial Receptivity and Clinical Outcomes in Assisted Reproductive Technology Cycles

Introduction Assisted reproductive technologies (ART) rely on endometrial receptivity (ER) for successful embryo implantation. This study aimed to compare the impact of different progesterone administration routes on ER assessed using optimal time for endometrial receptivity analysis (OpERA) and clinical outcomes in ART cycles. Methods A retrospective cohort analysis was conducted on 281 infertile women who underwent in vitro fertilization (IVF). Patients were stratified based on progesterone administration routes: oral and vaginal progesterone (Group 1) vs. intramuscular progesterone (Group 2). OpERA was performed on 257 patients to assess ER. Clinical outcomes, including biochemical pregnancy rate (BPR), clinical pregnancy rate (CPR), implantation rate (IR), and abortion rate (AR), were compared between the groups. Results OpERA results showed no significant differences between Group 1 and Group 2 in receptive (51.2% vs. 52.0%, p = 0.857), pre-receptive (44.1% vs. 44.6%, p = 0.933), or post-receptive (4.7% vs. 3.1%, p = 0.496) states. Clinical outcomes, including BPR (59.9% vs. 60.9%, p = 0.903), CPR (50.0% vs. 56.5%, p = 0.463), IR (52.5% vs. 55.3%, p = 0.748), and AR (44.3% vs. 45.6%, p = 0.882), did not significantly differ between the groups. Conclusion Progesterone administration routes did not significantly affect ER or clinical outcomes, highlighting the need to prioritize understanding and enhancing ER instead of solely focusing on progesterone delivery methods. Identifying molecular pathways or biomarkers could improve receptivity and optimize ART, ultimately improving pregnancy outcomes.

[No improvement in live birth rate after luteal phase support by GnRH agonist]

OBJECTIVES

To evaluate the impact of adding a GnRH agonist (GnRH-a) in luteal phase support (LPS) on live birth rates in IVF/ICSI in antagonist protocols.

METHODS

In total, 341 IVF/ICSI attempts are analyzed in this retrospective study. Patients were divided into two groups: A f: LPS with progesterone alone (179 attempts) between March 2019 and May 2020; B: LPS with progesterone and an injection of triptorelin (GnRH-a) 0.1mg 6 days after oocyte retrieval (162 attempts) between June 2020 and June 2021. The primary outcome was live birth rate. The secondary outcomes were miscarriage rate, pregnancy rate and ovarian hyperstimulation syndrome rate.

RESULTS

The baseline characteristic are identical between the two groups except the infertility duration (longer in the group B). There was no significant difference between the two groups in live birth rate (24.1% versus 21.2%), pregnancy rate (33.3% versus 28.1%), miscarriage rate (4.9% versus 3.4%) and no increase the SHSO rate. The multivariate regression analysis after adjustment for age, ovarian reserve and infertility duration did not reveal a significant difference in live birth rate between the two groups.

CONCLUSION

In this study, the results showed no statistically significant association with the single injection of a GnRH-a in addition to progesterone on live birth rate in luteal phase support.

[Comparison of oral dydrogesterone with micronized vaginal progesterone in fresh embryo transfert in IVF/ICSI]

INTRODUCTION

Luteal insufficiency corresponds to a progesterone deficiency affecting women who receive treatment for in vitro fertilization (IVF). Different routes of progesterone administration exist and have varying degrees of acceptability to patients. The aim of this study was to compare two luteal phase support (LPS) treatments: oral dydrogesterone versus micronized vaginal progesterone on the clinical pregnancy occurrence after fresh embryo transfer.

MATERIAL AND METHODS

This study was a monocentric historical and observational cohort study carried out in the reproductive medicine department at the University Hospital, Femme Mère Enfant in Lyon. All the data were collected retrospectively. Women between 18 and 43 years old, who completed an IVF cycle with or without ICSI, followed by fresh embryo transfer on the second or third day after oocyte retrieval (D2 or D3) or at the blastocyst stage (D5 or D6) between July 2019 and July 2020 were included. The 290 patients included between July 2019 and January 2020 received 600mg per day of PMV. The 290 patients in the OD group included between January and July 2020 received 30mg OD per day.

RESULTS

In the univariate analysis, the clinical pregnancy occurrence per transfer was comparable between the MVP and OD groups (P>0.05) (OR [95% CI]): 0.904 [0.630 ; 1.296]. In the multivariate analysis, OD also appeared to be associated with a similar pregnancy occurrence compared to MVP, with a non-significant difference (OR [95% CI]): 0.940 [0.640; 1.380]. The use of OD compared to MVP did not significantly influence the clinical pregnancy occurrence in any age group. There was no significant difference between the two groups in the clinical pregnancy occurrence, whether the patients belonged to the reference population of the center or not (P>0.05) (OR [95% CI]): 2.367 [0.568; 3.568].

CONCLUSION

This important French retrospective study confirms the safety and efficacy of OD.

[Dydrogesterone versus micronized vaginal progesterone as luteal phase support after fresh embryo transfer in IVF]

OBJECTIVES

The objective of the study was to compare the live birth rate and miscarriage rate after fresh embryo transfer (Fresh ET) when patients are treated either with oral dydrogesterone or micronized vaginal progesterone (MVP) as luteal phase support (LPS). The vaginal route is still preferred, despite the discomfort for the patients and recent RCTs showing similar results for dydrogesterone and MVP.

METHODS

All 556 consecutive Fresh ET after autologous IVF procedure, from December 2011 to March 2013 in one centre in France were included. Patients were treated either with dydrogesterone 10mg every 12hours (n=267) or MVP 200mg every 12hours (n=289), the physician's arbitrary choice on the day of the oocyte aspiration procedure.

RESULTS

The groups were comparable regarding the demographic data and stimulation protocols, except for the rank of the oocyte pickup procedure [1.54±0.80 vs. 1.74±0.96, (P=0.01)], with no significant difference in live birth rates (22.4% vs. 23.8%, P=0.77) and miscarriage rates (4.1% vs. 5.5%, P=0.55) for dydrogesterone vs. MVP respectively. The results were similar in a good prognosis patients' subgroup.

CONCLUSIONS

LPS with either dydrogesterone or MVP after Fresh ET showed similar live birth rates and miscarriage rates. The benefits of the oral over vaginal route might be higher tolerance and possibly better compliance. Dydrogesterone seems to be a safe treatment, but its long-term innocuity needs to be further proven.

Ovarian Follicular Growth through Intermittent Vaginal Gonadotropin Administration in Diminished Ovarian Reserve Women

It is a challenge to obtain enough oocytes during in vitro fertilization (IVF) in women who have a poor ovarian response (POR) in achieving conception. We have adopted the characteristics of the first uterine pass effect, which we pioneered in employing the vaginal administration of gonadotropins in women receiving IVF treatments. In our previous study employing vaginal administration, faster absorption and slower elimination of gonadotropins were demonstrated, and, female subjects presented proper ovarian follicle growth and pregnancy rates. In this study, during 2016–2020, 300 to 675 IU of gonadotropins were administered vaginally every three days in 266 POR women for their controlled ovarian hyperstimulation (COH). The injections were performed with needles angled at 15–30° towards the middle-upper portions of the bilateral vaginal wall, with an injection depth of 1–2 mm. For the COH results, these women, on average, received 3.0 ± 0.9 vaginal injections and a total dose of 1318.4 ± 634.4 IU gonadotropins, resulting in 2.2 ± 1.9 mature oocytes and 1.0 ± 1.2 good embryos. Among these embryos, 0.9 ± 1.0 were transferred to reach a clinical pregnancy rate of 18.1% and a live birth rate of 16.7%. In conclusion, the intermittent vaginal administration of gonadotropins proved to be effective in POR women for their IVF treatments.

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.

Systematic use of long-acting intramuscular progesterone in addition to oral dydrogesterone as luteal phase support for single fresh blastocyst transfer: A pilot study

OBJECTIVE

The need of luteal support after FET is no longer to be proven. Different routes of progesterone administration are available with interindividual differences in metabolization and serum progesterone levels, the latter being highly correlated with pregnancy and delivery rates. The administration of 2 different routes of progestogen significantly improves success rates in FET. The aim of the current study was to investigate the added value to combine intramuscular administration of progesterone to dydrogesterone in fresh embryo transfer.

METHODS

This is a retrospective study from prospectively collected data. Patient, aged between 18 and 43 years old, had received a fresh blastocyst transfer between January 2021 and June 2021. In the first group, all patients received only oral dydrogesterone 10mg, three times a day, beginning the evening of oocyte retrieval. In the second group, patients received, in addition to dydrogesterone, a weekly intramuscular injection of progesterone started the day of embryo transfer. Primary endpoint was ongoing pregnancy rate.

RESULTS

171 fresh single blastocyst transfers have been performed during this period. 82 patients were included in "dydrogesterone only" and 89 patients in "dydrogesterone + IM". Our two groups were comparable except for body mass index. After adjustment on BMI, our two groups were comparable regarding implantation rate, early pregnancy rate (46.1 versus 54.9, OR 1.44 [0.78; 2.67], p=0.25) miscarriage rate, ongoing pregnancy rate (30.3 versus 43.9, OR 1.85 [0.97; 3.53] p= 0.06).

CONCLUSION

Using systematically long acting intramuscular progesterone injection in addition to oral dydrogesterone as luteal phase support seems to have no significant impact on IVF outcomes when a single fresh blastocyst transfer is performed.

Luteal-phase support in assisted reproductive technology: An ongoing challenge

It has been shown that in controlled ovarian hyper stimulation cycles, defective luteal phase is common. There are many protocols for improving pregnancy outcomes in women undergoing fresh and frozen in vitro fertilization cycles. These approaches include progesterone supplements, human chorionic gonadotropin, estradiol, gonadotropin-releasing hormone agonist, and recombinant luteinizing hormone. The main challenge is luteal-phase support (LPS) in cycles with gonadotropin-releasing hormone agonist triggering. There is still controversy about the optimal component and time for starting LPS in assisted reproductive technology cycles. This review aims to summarize the various protocols suggested for LPS in in vitro fertilization cycles.

Ovarian Folliculogenesis and Uterine Endometrial Receptivity after Intermittent Vaginal Injection of Recombinant Human Follicle-Stimulating Hormone in Infertile Women Receiving In Vitro Fertilization and in Immature Female Rats

The uterine first-pass effect occurs when drugs are delivered vaginally. However, the effect of vaginally administered recombinant human follicle-stimulating hormone (rhFSH) on ovarian folliculogenesis and endometrial receptivity is not well established. We aimed to compare the efficacy of rhFSH administered vaginally and abdominally in clinical in vitro fertilization (IVF) treatment, pharmacokinetic study, and animal study. In IVF treatment, the number of oocytes retrieved, endometrial thickness and uterine artery blood perfusion were not different between women who received the rhFSH either vaginally or abdominally. For serum pharmacokinetic parameters, significantly lower Tmax, clearance, and higher AUC and T_1/2_elimination of rhFSH were observed in women who received rhFSH vaginally, but urine parameters were not different. Immature female rats that received daily abdominal or vaginal injections (1 IU twice daily for 4 days) or intermittent vaginal injections (4 IU every other day for two doses) of rhFSH had more total follicles than the control group. In addition, the serum progesterone and progesterone receptors in the local endometrium were significantly higher in the groups treated with intermittent abdominal or vaginal injection of rhFSH, compared with those who recieved daily injection. In summary, vaginal administration of rhFSH may provide an alternative treatment regimen in women receiving IVF.

Analysis of serum and endometrial progesterone in determining endometrial receptivity

STUDY QUESTION

Is there a relationship between serum and endometrial progesterone (P4) levels, including P4 and metabolites (oestrone, oestradiol and 17α-hydroxyprogesterone), and endometrial receptivity?

SUMMARY ANSWER

Serum P4 levels were not correlated with endometrial P4, nor associated with endometrial receptivity as determined by the ERA® test; however, endometrial P4 and 17α-hydroxyprogesterone levels were positively correlated and related to endometrial receptivity by ERA.

WHAT IS KNOWN ALREADY

Acquisition of endometrial receptivity is governed by P4, which induces secretory transformation. A close relationship between serum P4 and pregnancy outcome is reported for hormone replacement therapy (HRT) cycles. However, the relationship between serum and uterine P4 levels has not been described, and it is unknown whether uterine receptivity depends more on serum or uterine P4 levels.

STUDY DESIGN, SIZE, DURATION

A prospective cohort study was performed during March 2018-2019 in 85 IVF patients undergoing an evaluation-only HRT cycle with oestradiol valerate (6 mg/day) and micronised vaginal progesterone (400 mg/12 h).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Patients were under 50 years of age, had undergone at least one failed IVF cycle, had no uterine pathology, and had adequate endometrial thickness (> 6.5 mm). The study was conducted at IVI Valencia and IVI Foundation. An endometrial biopsy and a blood sample were collected after 5 days of P4 vaginal treatment. Measures included serum P4 levels, ERA®-based evaluation of endometrial receptivity, and endometrial P4 levels along with metabolites (oestrone, oestradiol and 17α-hydroxyprogesterone) measured by ultra-performance liquid chromatography-tandem mass spectrometry.

MAIN RESULTS AND THE ROLE OF CHANCE

Seventy-nine women were included (mean age: 39.9 ± 4.6, BMI: 24.2 ± 3.9 kg/m2, endometrial thickness: 8.2 ± 1.4 mm). The percentage of endometria indicated as receptive by ERA® was 40.5%. When comparing receptive versus non-receptive groups, no differences were observed in baseline characteristics nor in steroid hormones levels in serum or endometrium. No association between serum P4 and endometrial steroid levels or ERA result was found (P < 0.05). When the population was stratified according to metabolite concentration levels, endometrial P4 and 17α-hydroxyprogesterone were significantly associated with endometrial receptivity (P < 0.05). A higher proportion of receptive endometria by ERA was observed when endometrial P4 levels were higher than 40.07 µg/ml (relative maximum) and a lower proportion of receptive endometria was associated with endometrial 17α-hydroxyprogesterone lower than 0.35 ng/ml (first quartile). A positive correlation R2 = 0.67, P < 0.001 was observed between endometrial P4 and 17α-hydroxyprogesterone levels.

LIMITATIONS, REASONS FOR CAUTION

This study did not analyse pregnancy outcomes. Further, the findings can only be extrapolated to HRT cycles with micronised vaginal progesterone for luteal phase support.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings suggest that the combined benefits of different routes of progesterone administration for luteal phase support could be leveraged to ensure an adequate concentration of progesterone both in the uterus and in the bloodstream. Further studies will confirm whether this method can optimise both endometrial receptivity and live birth rate. Additionally, targeted treatment to increase P4 endometrial levels may normalise the timing of the window of implantation without needing to modify the progesterone administration day.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by the IVI-RMA Valencia (1706-VLC-051-EL) and Consellería d'Educació, Investigació, Cultura, i esport Generalitat Valenciana (Valencian Government, Spain, GV/2018//151). Almudena Devesa-Peiro (FPU/15/01398) and Cristina Rodriguez-Varela (FPU18/01657) were supported by the FPU program fellowship from the Ministry of Science, Innovation and Universities (Spanish Government). P.D.-G. is co-inventor on the ERA patent, with non-economic benefits. The other authors have no competing interests.

TRIAL REGISTRATION NUMBER

NCT03456375.

New concepts and difficulties with progesterone supplementation in the luteal phase

PURPOSE OF REVIEW

Management of the luteal phase (LP) in assisted reproductive cycles has aroused interest in recent years. The reason is that it seems that the individualization of LP support may be necessary, since the concept of 'one size fits all' does not apply to this treatment.

RECENT FINDINGS

Studies carried out in hormone replacement therapy cycles (also called artificial cycles) have shown that serum levels of progesterone (P) are related to pregnancy outcomes. This represents a milestone in the management of artificial cycles (AC), because until a few years ago it was believed that serum levels did not really reflect the effectiveness of P, which is why they were neglected. However, it is not as straightforward as it seems, because the interpretation of serum progesterone values will depend on the type of progesterone used and its route of administration. Likewise, the findings observed in AC are not applicable to what occurs in a fresh transfer cycle after ovarian stimulation or an embryo transfer in the context of a natural cycle.

SUMMARY

In this manuscript, we will summarize the current situation in LP management.

The early luteal hormonal profile in IVF patients triggered with hCG

STUDY QUESTION

What is the early luteal phase hormonal profile in patients undergoing ovarian stimulation for IVF/ICSI followed by hCG trigger and a freeze-all strategy without luteal phase support?

SUMMARY ANSWER

The peak concentration of progesterone occurred 4 days after oocyte pick-up (OPU + 4), with an average 35% fall from OPU + 4 to OPU + 6, and progesterone levels before and 12 h after hCG administration predicted levels during the early luteal phase.

WHAT IS KNOWN ALREADY

The luteal phase during IVF differs from that during normal cycles, particularly with respect to the serum progesterone level profile. This can cause asynchrony between the embryo and the endometrium, potentially resulting in implantation failure and poor reproductive outcomes.

STUDY DESIGN, SIZE, DURATION

This prospective study included 161 women with normal ovarian reserve receiving GnRH antagonist co-treatment during ovarian stimulation with FSH who were followed up to 6 days after OPU in a single IVF cycle.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women aged 18-42 years undergoing IVF with ovarian stimulation using FSH were included. Ovulation was triggered with recombinant hCG 250 μg. Hormone levels were determined from blood samples taken on the day of trigger, before hCG, at 12, 24 and 36 h after hCG and at 1, 2, 3, 4, 5 and 6 days after OPU. The primary endpoint was early luteal phase serum concentrations of progesterone, LH, estradiol and hCG.

MAIN RESULTS AND THE ROLE OF CHANCE

One outlier with a pre-hCG serum progesterone level of 11.42 ng/mL was excluded, so all analyses included 160 subjects. Progesterone levels began to increase 1 day after OPU, peaked 4 days after OPU (114 ng/mL), then declined from OPU + 5 onwards. Peak progesterone levels were at OPU + 4, OPU + 5 or OPU + 6 in 38.8, 29.4 and 13.8% of patients, respectively. Approximately two-thirds of patients had a fall in serum progesterone from OPU + 4 to OPU + 6. Pre-hCG progesterone levels correlated significantly with those at 24 h after hCG (r2 = 0.28; P < 0.001), which in turn correlated significantly with progesterone at OPU + 4 (r2 = 0.32; P < 0.001). LH peaked (4.4 IU/L) 12 h after hCG trigger, persisting for 24 h but was barely elevated compared with physiological levels. Serum estradiol peaked twice: at 24 h post-trigger and at OPU + 4. Highest hCG levels (130 mIU/mL) occurred at 24 h post-injection. The best correlations between the number of follicles ≥11 mm and serum progesterone level were seen at 24 and 36 h after hCG and OPU + 1.

LIMITATIONS, REASONS FOR CAUTION

The influence of different profiles of serum progesterone on reproductive outcomes could not be determined because a freeze-all strategy was used in all patients. In addition, data were not available to relate serum hormone level findings with endometrial histology or endometrial receptivity analysis to clearly identify the relationship between serum hormones and the window of implantation.

WIDER IMPLICATIONS OF THE FINDINGS

Detailed information about early luteal phase hormone levels could be used to optimize and individualize luteal phase support to improve reproductive outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by My Duc Hospital, Ho Chi Minh City, Vietnam. All authors state that they have no conflicts of interest to disclose.

TRIAL REGISTRATION NUMBER

NCT02798146; NCT03174691.

What is the optimal luteal support in assisted reproductive technology?

The need for luteal phase support in IVF/ICSI is well established. A large effort has been made in the attempt to identify the optimal type, start, route, dosage and duration of luteal phase support for IVF/ICSI and frozen embryo transfer. These questions are further complicated by the different types of stimulation protocols and ovulation triggers used in ART. The aim of this review is to supply a comprehensive overview of the available types of luteal phase support, and the indications for their use.A review of the literature was carried out in the effort to find the optimal luteal phase support regimen with regards to pregnancy related outcomes and short and long term safety.The results demonstrate that vaginal, intramuscular, subcutaneous and rectal progesterone are equally effective as luteal phase support in IVF/ICSI. GnRH agonists and oral dydrogesterone are new and promising treatment modalities but more research is needed. hCG and estradiol are not recommended for luteal phase support. More research is needed to establish the most optimal luteal phase support in frozen embryo transfer cycles, but progesterone has been shown to improve live birth rate in some studies. Luteal phase support should be commenced between the evening of the day of oocyte retrieval, and day three after oocyte retrieval and it should be continued at least until the day of positive pregnancy test.So, in conclusion still more large and well-designed RCT's are needed to establish the most optimal luteal phase support in each stimulation protocol, and especially in frozen embryo transfer.

Dydrogesterone as an oral alternative to vaginal progesterone for IVF luteal phase support: A systematic review and individual participant data meta-analysis

The aim of this systematic review and meta-analysis was to conduct a comprehensive assessment of the evidence on the efficacy and safety of oral dydrogesterone versus micronized vaginal progesterone (MVP) for luteal phase support. Embase and MEDLINE were searched for studies that evaluated the effect of luteal phase support with daily administration of oral dydrogesterone (20 to 40 mg) versus MVP capsules (600 to 800 mg) or gel (90 mg) on pregnancy or live birth rates in women undergoing fresh-cycle IVF (protocol registered at PROSPERO [CRD42018105949]). Individual participant data (IPD) were extracted for the primary analysis where available and aggregate data were extracted for the secondary analysis. Nine studies were eligible for inclusion; two studies had suitable IPD (full analysis sample: n = 1957). In the meta-analysis of IPD, oral dydrogesterone was associated with a significantly higher chance of ongoing pregnancy at 12 weeks of gestation (odds ratio [OR], 1.32; 95% confidence interval [CI], 1.08 to 1.61; P = 0.0075) and live birth (OR, 1.28; 95% CI, 1.04 to 1.57; P = 0.0214) compared to MVP. A meta-analysis combining IPD and aggregate data for all nine studies also demonstrated a statistically significant difference between oral dydrogesterone and MVP (pregnancy: OR, 1.16; 95% CI, 1.01 to 1.34; P = 0.04; live birth: OR, 1.19; 95% CI, 1.03 to 1.38; P = 0.02). Safety parameters were similar between the two groups. Collectively, this study indicates that a higher pregnancy rate and live birth rate may be obtained in women receiving oral dydrogesterone versus MVP for luteal phase support.

Shortcomings of an unphysiological triggering of oocyte maturation using human chorionic gonadotropin

Final maturation of follicles has, in connection with ovarian stimulation and infertility treatment, traditionally been achieved by the administration of a human chorionic gonadotropin (hCG) bolus trigger of 5,000 to 10,000 IU. This trigger serves two purposes: induce oocyte maturation; and serve as luteal phase support owing to its long half-life. It now appears that the hCG bolus trigger is unable to support both these two purposes optimally. In particular, after an hCG trigger, the early luteal phase is hormonally abnormal and different from conditions observed in the natural menstrual cycle: the timing of the initiation of hCG and progesterone rise is much faster after an hCG trigger than in a natural menstrual cycle; the maximal concentrations of hCG and progesterone considerably exceed those naturally observed; and the timing of the peak progesterone concentration after an hCG trigger is advanced several days compared with the natural cycle. Furthermore, the hCG trigger without any follicle-stimulating hormone activity may induce oocyte maturation less efficiently than the combined luteinizing hormone and follicle-stimulating hormone surge normally seen. Collectively, the endometrium is likely to be advanced after an hCG trigger, and the implantation potential is probably not optimal. The precise effect on pregnancy rates after the different progressions of hCG and progesterone concentrations during the early luteal phase has not yet been determined, but more individualized methods using more physiological approaches are likely to improve reproductive outcomes.

Progesterone use in assisted reproductive technology

Progesterone is the main hormone in the luteal phase. It plays a key role in preparing the uterus for a possible pregnancy, and in maintaining it after it has occurred. In assisted reproduction treatments, there is usually a luteal phase deficiency, so it is necessary to supplement this critical phase to obtain the best results, not only of implantation but also of ongoing pregnancy. Among all the available options, exogenously administered progestogens are the most used, as they have proven their efficacy and safety. This review will address the most relevant aspects of luteal phase support with progesterone in the different scenarios an embryo transfer can be performed, such as the stimulated cycle, the artificial cycle, or the natural cycle. Although there is no evidence of the perfect protocol for all patients, recent studies point to the need of individualizing luteal phase support according to the needs of each patient.

Anogenital distance in newborn infants conceived by assisted reproduction and natural conception

RESEARCH QUESTION

Does anogenital distance (AGD) differ in newborn infants conceived through assisted reproduction technology (ART) compared with those conceived naturally?

DESIGN

This case-control study looked at anthropometric and anogenital measurements in 247 male and 200 female newborns born after ART (n = 121) or natural conception (n = 326), within 24 h of birth. Anogenital measurements included distance from the centre of the anus to the anterior clitoris (AGDAC) and to the posterior fourchette (AGDAF) in female infants, and from the centre of the anus to the posterior base of the scrotum (AGDAS) and to the anterior base of the penis (AGDAP) in male infants.

RESULTS

ART mothers were older, more likely to be nulliparous and delivered by Caesarean section at an earlier gestational week. AGDAS of male infants was approximately twice the AGDAF of female infants (17.6 ± 5.0 versus 9.1 ± 3.6 mm). AGDAF in female infants conceived by ART compared with those conceived naturally was not significantly different (8.8 ± 3.6 versus 9.3 ± 3.6 mm; P = 0.404). AGDAC were also comparable for both groups (27.4 ± 6.3 versus 27.7 ± 7.1 mm; P = 0.770). In male infants, no significant difference was seen between ART and natural conception groups in terms of AGDAS (17.4 ± 4.6 versus 17.7 ± 5.2 mm, P = 0.742) and AGDAP (37.5 ± 6.6 versus 38.0 ± 6.7 mm, P = 0.589). When adjusted for gestational age, weight, length and head circumference, mode of conception was not associated with differences in any of the anogenital measurements.

CONCLUSIONS

AGD measurements in infants conceived by ART are no different from those of infants conceived naturally.

The strength of evidence supporting luteal phase progestogen after assisted reproduction: A systematic review with reference to trial registration and pre-specified endpoints

OBJECTIVE

To measure the potential for outcome switching and selective reporting, in trials of luteal phase progestogen in assisted reproduction.

STUDY DESIGN

Trials identified through Medline and Embase in August 2017 using the MeSH term "assisted reproductive technology, luteal phase support" and associated text words. Randomised controlled trials (RCTs) comparing progestogen of any type, dose, and route of administration, with placebo or no treatment as luteal phase support in subfertile women undergoing in vitro fertilization (IVF) or intrauterine insemination (IUI). Eight trials after IVF and eleven after IUI, involving 1040 and 2764 participants respectively, were included.

RESULTS

None of the eight trials of progestogen therapy after IVF had been registered. Only 5/11 trials of progestogen after IUI had been registered, and only two of these prospectively. One of these had a registered primary outcome of "pregnancy sac plus heartbeat", but reported "pregnancy sac alone"; we judged this as an altered primary outcome. Three other trial had a registered primary outcome of "clinical pregnancy undefined" and reported "intra or extra-uterine pregnancy with a heartbeat"; we judged this alteration as minimal. That trial was negative. Overall, 26 different outcomes had been reported by the various trials. The three outcomes reported most often were pregnancy undefined (9/19), miscarriage (11/19) and clinical pregnancy (9/19). This suggests considerable potential for selective outcome reporting or outcome switching.

CONCLUSION

Apart from one negative trial, none of the evidence on luteal phase progestogen after assisted reproduction comes from prospectively registered trials: a slender reed indeed.

The Influence Of Intrauterine Pressure On Embryo Retention In A Catheter After Embryo Transfer

The retention of the embryo in the transfer catheter after embryo transfer (ET) during in vitro fertilization is a very common phenomenon, encountered by even the most experienced operators, and embryos retained in the transfer catheter or its sleeve require a repeat transfer. The exact mechanism of embryo retention has not been explained. Therefore, the present study aimed to investigate the mechanism of embryo retention in the catheter during embryo transfer by using a transparent uterus model equipped with pressure sensors and a video recorder. The results indicate that pressure changes in the uterine cavity during ET can influence the distribution of the transferred fluid containing the embryo. Under certain conditions, the transferred fluid can flow backward in the catheter, which may lead to retention of the embryo in the catheter.