The effect of estradiol depletion during the luteal phase on endometrial development

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.

Duration of estradiol supplementation in luteal phase support for frozen embryo transfer in hormone replacement treatment cycles: a randomized, controlled phase III trial

PURPOSE

In this study, we intend to evaluate pregnancy outcomes in women who undergo artificial frozen embryo transfer (FET) and stop estradiol (E2) after vaginal ultrasound observation of a gestational sac and heartbeat.

METHODS

In this randomized phase III clinical trial, we recruited 291 patients who underwent FET. We randomly assigned 64 pregnant women to a study or a control group after observation of a gestational sac and heartbeat at 6-week gestational age. E2 administration continued until week 12 of gestational age for the control group, but was discontinued for the study group. Progesterone-in-oil administration continued until week 12 of gestational age for both groups. Serum levels for E2 and progesterone were measured on the initial progesterone and embryo transfer (ET) days, and at weeks 6 and 12 of pregnancy in both groups.

RESULTS

The miscarriage rate was 1/32 (3.13%) in the study group and 6/32 (18.75%) in the control group after the intervention and confirmation of a fetal heartbeat. This difference was statistically significant. All patients who remained under intervention, which included 29 in the study group and 24 in the control group, had live births. Although the mean serum E2 and progesterone levels steadily increased from the initial day of progesterone administration to week 12 of gestational age, they were not significantly different between the two groups. Maternal complications were significantly more common in the control group.

CONCLUSION

Earlier discontinuation of E2 for luteal phase support of FET cycles may be taken into consideration. Additional clinical studies should be conducted to determine an accurate estimation of the time when E2 should be discontinued during FET luteal phase support.

TRIAL REGISTRATION

NCT04013438, registered 9 July 2019-Retrospectively registered, https://www.clinicaltrials.gov/ct2/show/NCT04013438?cond=NCT04013438&draw=2&rank=1.

A comparison of the effects of three luteal phase support protocols with estrogen on in vitro fertilization-embryo transfer outcomes in patients on a GnRH antagonist protocol

Objective:

This study aimed to evaluate the effects of three different luteal phase support protocols with estrogen on the pregnancy rates and luteal phase hormone profiles of patients undergoing in vitro fertilization-embryo transfer (IVF-ET) cycles. A secondary objective was to evaluate which ovarian reserve markers correlated with pregnancy rates.

Methods:

This retrospective observational study was carried out at a private tertiary reproductive medicine teaching and research center. The study enrolled 104 patients undergoing intracytoplasmic sperm injection (ICSI) on an antagonist protocol for controlled ovarian hyperstimulation (COH). The women were divided into three groups based on the route of administration of estrogen (E2) for luteal phase support: oral (Primogyna); transdermal patches (Estradott); or transdermal gel (Oestrogel Pump). The administration of estrogen provided the equivalent to 4 mg of estradiol daily. All women received 600mg of vaginal progesterone (P) per day (Utrogestan) for luteal phase support. Blood samples were drawn on the day of hCG administration and on the day of beta hCG testing to measure E2 and P levels. Clinical pregnancy rate (PR) was the main endpoint.

Results:

The patients included in the three groups were comparable. No significant differences were found in implantation rates, clinical PR, miscarriage rates, multiple-pregnancy rates, E2 or P levels on the day of beta hCG measurement. Concerning ovarian reserve markers, significant correlations between testing positive for clinical pregnancy and AMH (r = 0.66, p<0.0001) and E2 levels on beta hCG measurement day (r = 0.77; p<.0001) were observed.

Conclusions:

No significant differences were seen in the pregnancy rates of patients submitted to IVF-ET cycles with GnRH antagonists given oral, transdermal patches, or transdermal gel E2 during the luteal phase. A correlation was found between clinical pregnancy rate and AMH and E2 levels on beta hCG testing day.

Endometrial preparation for third-party parenting and cryopreserved embryo transfer

The advent of third party parenting ushered in the era of artificial stimulation of the endometrium. Initially intended only for patients with ovarian failure, exogenous induction of endometrial receptivity was quickly shown to be as good as natural endometrial preparation, with the advantage that the timing of embryo transfer could be controlled. It is perhaps surprising that even though the ovary produces a variety of steroids, that estradiol (E₂) and progesterone (P) alone would be needed to achieve optimal receptivity; no other substance has ever been shown to improve on the basic regimen of E₂ and P. A variety of routes of administration are available for both E₂ and P and physiologic (or supraphysiologic) serum or endometrial tissue levels of both can be achieved. The optimal duration of E₂ stimulation and the timing of the onset of P administration continue to be debated, but it appears that imitating the sequence that normally occurs in nature leads to optimal results. The poorly responsive endometrium and cases of recurrent implantation failure remain a challenge, but the clear majority of patients can successfully achieve pregnancy as long as embryos of adequate quality are transferred.

Oestrogen dose tapering during luteal phase does not affect clinical outcomes after hormone replacement treatment-frozen-thawed embryo transfer cycles: a retrospective analysis

STUDY QUESTION

Does oestrogen dose tapering during the luteal phase affect the clinical outcome after hormone replacement treatment-frozen-thawed embryo transfer (HRT-FET) cycles?

SUMMARY ANSWER

Our results suggest that tapering oestrogen doses during the luteal phase results in similar clinical outcomes to those obtained with the traditional luteal phase support (LPS).

WHAT IS KNOWN ALREADY

Traditional LPS with oestrogen and progesterone is considered necessary in HRT-FET cycles. However, case reports have shown successful clinical pregnancies and live births in the absence of oestrogen administration after embryo transfers.

STUDY DESIGN, SIZE, DURATION

This was a retrospective study on 6035 HRT-FET cycles extending over 7 years from January 2011 to June 2018 at the reproductive medicine centre of Xiangya Hospital.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We compared the clinical outcomes of 1632 HRT-FET cycles with tapered oestrogen doses from 12 days after embryo transfer (study group) to those of 4403 HRT-FET cycles maintained on constant oestrogen doses during the luteal phase (control group) in the case of positive serum HCG test.

MAIN RESULTS AND THE ROLE OF CHANCE

We found similar biochemical pregnancy rates (52.1% vs. 51.9, P = 0.864), clinical pregnancy rates (44.9% vs. 43.2%, P = 0.249), implantation rates (29.8% vs. 29.3%, P = 0.591) and miscarriage rates (16.0% vs. 14.6%, P = 0.379) between the studied groups.

LIMITATIONS, REASONS FOR CAUTION

Retrospective, design-associated biases are possible. In addition, some baseline characteristics differed between groups. Finally, we did not compare live birth rates between groups.

WIDER IMPLICATIONS OF THE FINDINGS

Our study showing similar outcomes between traditional LPS and oestrogen tapering during the luteal phase indicates that oestrogen may be cautiously tapered during the luteal phase after HRT-FET cycles.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the National Natural Science Foundation of China (grant no. 81401269) and the class General Financial Grant from the China Postdoctoral Science Foundation (grant no. 2017M620360). The authors declare that they have no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Luteal oestradiol for patients with serum oestradiol levels lower than expected per oocyte

Although the efficiency of progesterone in providing luteal phase support has been established, the role of oestradiol supplementation during the luteal phase remains controversial. We evaluated pregnancy outcomes of patients who had a ratio of serum E2 levels on the hCG day to the number of oocytes retrieved (oestradiol/oocyte ratio - EOR) levels of <100 pg/ml by supporting them with additional oestradiol during the luteal phase. In total, 150 patients with an EOR < 100 pg/ml of oestradiol undergoing antagonist intracytoplasmic sperm injection (ICSI) cycles were randomly assigned into two groups to receive either oral oestradiol (4 mg/d) plus vaginal progesterone (90 mg, 2 × 1/day) (group 1) or vaginal progesterone (90 mg, 2 × 1/d) alone (group 2). Implantation rate following transfer of a single embryo did not differ between the two groups (group 1 = 33.3%; group 2 = 34.9%; p = 0.85). Similarly, both groups gave comparable clinical pregnancy rates per embryo transfer with 31.7% in group 1 compared with 28.6% in group 2 (p = 0.69). In conclusion the study suggests that the addition of 4 mg oral E2 to progesterone does not increase the probability of pregnancy.

Luteal phase support with estradiol and progesterone versus progesterone alone in GnRH antagonist ICSI cycles: a randomized controlled study

In vitro fertilization (IVF) cycles are associated with a defective luteal phase. Although progesterone supplementation to treat this problem is standard practice, estrogen addition is debatable. Our aim was to compare pregnancy outcomes in 220 patients undergoing antagonist intracytoplasmic sperm injection (ICSI) cycles protocol. The patients were randomly assigned into two equal groups to receive either vaginal progesterone alone (90 mg once daily) starting on the day of oocyte retrieval for up to 12 weeks if pregnancy occurred or estradiol addition (2 mg twice daily) starting on the same day and continuing up to seven weeks (foetal viability scan). Primary outcomes were pregnancy and ongoing pregnancy rates per embryo transfer. Secondary outcomes were implantation and early pregnancy loss rates. Pregnancy rates showed no significant difference between group 1 (39.09%) and 2 (43.63%) (p value = 0.3). Similarly, both groups were comparable regarding ongoing pregnancy rate (32.7% group 1 and 36.3% group 2, p value = 0.1). Implantation rates showed no difference between group 1 (19.25%) and group 2 (23.44%) (p value = 0.2). Early pregnancy loss rates were comparable, with 6.3% and 7.2% in groups 1 and 2, respectively, (p value = 0.4). In conclusion, the addition of 4 mg estrogen daily to progesterone for luteal support in antagonist ICSI cycles is not beneficial for pregnancy outcome.

Effect of single post-ovulatory administration of mifepristone (RU486) on transcript profile during the receptive period in human endometrium

Progesterone regulates uterine function during the luteal phase and is essential for the acquisition of endometrial receptivity. The objective of the present study was to identify endometrial transcripts whose expression is altered during the window of implantation after the administration of 200 mg of the antiprogestin mifepristone, 48 h after the LH peak (LH+2, LH+0=LH peak), and to determine the relationship of these transcripts with those regulated during the acquisition of receptivity. Endometrial samples were obtained in LH+7 from seven women of proven fertility, each one contributing with one cycle treated with placebo and another with mifepristone. Additionally, endometrial samples were obtained in LH+2 and LH+7 during a single untreated spontaneous cycle from seven normal fertile women as a reference. DNA microarrays were used to identify transcripts significantly regulated (defined as ≥2.0-fold change with false discovery rate below 1% usingt-test) with the administration of mifepristone vs placebo, or during the transition from pre-receptive to receptive (LH+2 vs LH+7). Approximately 2000 transcripts were significantly regulated in both comparisons (mifepristone vs placebo and LH+2 vs LH+7), but only 777 of them were coincident and displayed opposite regulation except for 25. The mRNA level for eight selected genes regulated by mifepristone was confirmed by real-time RT-PCR. We conclude that not all changes in endometrial transcript levels occurring in the transition from LH+2 to LH+7 seem to be regulated by the progesterone receptor and ∼37% of the genes whose transcript levels changed by effect of mifepristone could be associated with the acquisition of receptivity.

Estradiol supplementation during the luteal phase in poor responder patients undergoing in vitro fertilization: a randomized clinical trial

PURPOSE

This study was designed to evaluate the effects of adding Estradiol (E2) supplementation to progesterone (P) on improvement of pregnancy outcomes in poor responder patients who underwent in vitro fertilization (IVF).

METHODS

In a prospective randomized clinical trial, 118 poor responder patients, older than 38 years without contraindications of estradiol consumption from Infertility clinic of a university hospital were randomly divided (by computerized software) into two groups. Control group (59 patients) received only P and intervention group (59 patients) received P and E2 (4 mg/d). Supplementation was done with 4 mg E2 in the luteal phase. Fertilization rate, implantation rate, biochemical and clinical pregnancy rates, abortion rate, ongoing pregnancy, multiple pregnancy and ectopic pregnancy rates were documented for those who completed the study protocol in each group (per protocol analysis) and compared between groups.

RESULT

Fifty five patients in control group and 53 patients in intervention group successfully completed the study protocol. Treatment outcomes were not significantly different between two groups.

CONCLUSION

For poor responder women who underwent IVF, addition of E2 to P supplementation could not significantly improve pregnancy outcomes.

Maintenance of early pregnancy without early hormone support after frozen-thawed embryo transfer in hormone replacement treatment cycles

OBJECTIVE

To report two successful pregnancies after frozen-thawed ET in discontinued hormone replacement treatment cycles.

DESIGN

Case report.

SETTING

University hospital.

PATIENT(S)

Two infertile patients.

INTERVENTION(S)

Hormone replacement treatment for endometrial preparation and frozen-thawed ET.

MAIN OUTCOME MEASURE(S)

Ovarian ultrasonography, serial hormone measurements of serum E2 and P, successful pregnancy, and follow-up visit.

RESULT(S)

One patient discontinued both E2 and P support 2 weeks after ET. The other discontinued estrogen support on the day preceding ET. No spontaneous follicle development was observed by ultrasonography, and no increase in serum P concentration was observed. Both patients became pregnant and achieved deliveries.

CONCLUSION(S)

These two cases show that maintenance of pregnancy is possible without early hormone support in hormone replacement treatment cycles.

Outlook: Roles of FSH and LH during the follicular phase: insight into natural cycle IVF

A mounting interest in natural cycle IVF has challenged the medical community to better understand the mechanisms controlling the follicular phase and ovulation in particular, in an effort to optimize this procedure and its outcome. For practical reasons, the advancement of the follicular phase in the menstrual cycle is commonly timed according to the onset of last menses. However, this precludes knowing when the follicular phase truly begins and hampers the possibility of optimizing timing of late follicular-phase events, notably, the triggering of ovulation. Clinicians, therefore, use surrogate markers of follicular maturation, such as oestrogen production and follicular size. Because it is impossible to identify the low-amplitude intercycle basal FSH signal, efforts have reverted toward controlling when it takes place, either with exogenous oestrogen or with oral contraceptives. In the late follicular phase, the occurrence of LH surge results from a balance between the opposite effects of rising oestrogen concentrations, which favour the LH surge, and the opposing effects mediated by the gonadotrophin surge-attenuating factor, a peptide of ovarian origin. This review looks into the mechanisms that control these two hinges of the follicular phase, the basal FSH signal and LH surge, in the context of optimizing natural cycle IVF.

Luteal estrogen supplementation in stimulated cycles may improve the pregnancy rate in patients undergoing in vitro fertilization/intracytoplasmic sperm injection-embryo transfer

OBJECTIVE

To evaluate the effect of estradiol addition to progesterone supplementation during the luteal phase on pregnancy and implantation rates in patients undergoing in vitro fertilization/intracytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET) cycles.

METHODS

In this prospective, randomized study, carried out in an IVF unit of a university hospital, we studied patients who were undergoing IVF/ICSI with controlled ovarian hyperstimulation using a gonadotropin-releasing hormone agonist/human recombinant gonadotropin long protocol. The main outcome measures were the pregnancy and implantation rates measured in the two groups.

RESULTS

Our results suggest higher pregnancy and implantation rates in IVF/ICSI-ET cycles that were supplemented with estradiol in the luteal phase.

CONCLUSIONS

Estradiol supplementation during the luteal phase in women undergoing IVF/ICSI-ET has a beneficial effect on the outcome without (at least, as seems from this study) having any adverse effects.

Addition of estradiol to progesterone for luteal supplementation in patients stimulated with GnRH antagonist/rFSH for IVF: a randomized controlled trial

BACKGROUND

The role of progesterone for luteal support in stimulated cycles for IVF is well established. However, controversy still surrounds the benefit of additional supplementation with estradiol (E2) in GnRH agonist (GnRHa) cycles, while no such data are available for GnRH antagonists. The aim of this randomized controlled trial (RCT) was to compare ongoing pregnancy rates in patients stimulated with recombinant FSH (rFSH) and GnRH antagonist for IVF, who received micronized progesterone for luteal phase supplementation, with or without the addition of E2.

METHODS

Two hundred and one patients underwent ovarian stimulation with a fixed dose of 200 IU rFSH and GnRH antagonist. Patients were randomized to receive, for luteal phase supplementation, either 600 mg of micronized progesterone vaginally (n=100, progesterone group) or 600 mg of micronized progesterone and 4 mg of E2 valerate orally (n=101, progesterone/E2 group). The main outcome measure was ongoing pregnancy at 12 weeks per patient randomized.

RESULTS

Demographics, stimulation parameters and embryological data were comparable for the two groups compared. Twenty-six ongoing pregnancies were achieved in the progesterone (26%) and 30 in the progesterone/E2 group (29.7%). (Difference: 3.7 and 95%, CI: -15.8 to 8.6%).

CONCLUSION

It appears that the addition of E2 to progesterone in the luteal phase after stimulation with rFSH and GnRH antagonist does not enhance the probability of pregnancy.

Endometrial receptivity: Clinical assessment in relation to fertility, infertility, and antifertility

Fertility in humans and other mammalian species depends absolutely on synchronous events that render the developing blastocyst and the receiving uterus competent for implantation. Endometrial receptivity is defined as the period during which the endometrial epithelium acquires functional, but transient, ovarian steroid-dependent status supportive to blastocyst acceptance and implantation. Once inside the uterus, the blastocyst is surrounded by an intact luminal epithelium, which is considered to act as barrier to its attachment, except for this short period of high endometrial receptivity to blastocyst signal(s). Its transport and permeability properties, in conjunction with cellular action of the endometrium and the embryo, have been suggested to influence creation and maintenance of informational and nutritional status of uterine luminal milieu. This period, also termed as the 'window of implantation,' is limited to days 20-24 of menstrual cycle in humans. However, establishment of endometrial receptivity is still a biological mystery that remains unsolved despite marked advances in our understanding of endometrial physiology following extensive research associated with its development and function. This review deals with various structural, biochemical, and molecular events in the endometrium coordinated within the implantation window that constitute essential elements in the repertoire that signifies endometrial receptivity and is aimed to achieve a better understanding of its relationship to fertility, infertility, and for the development of targeted antifertility agents for human use and welfare.

What can the clinician do to improve implantation?

Implantation is a complicated process that requires the orchestration of a series of events involving both the embryo and the endometrium. Even with the transfer of high quality embryos, implantation rates remain relatively low. The growing tendency towards transferring fewer embryos provides further incentives to improve implantation rates. In this article, the various clinical strategies employed to increase the chance of implantation are reviewed. Embryo transfer technique is a critical step in assisted reproductive technology cycles. Recent studies have shown significant improvements in clinical pregnancy rates resulting from careful embryo transfer technique, appropriate catheter type and placing for embryo transfer. Increasingly, adjuvant pharmaceutical therapies are also being applied with the aim of improving embryo implantation. However, the evidence for their efficacy and safety is limited. Recent evidence suggests that adoption of milder ovarian stimulation regimens may provide a more effective clinical approach to improving implantation, since beneficial effects have been shown for both endometrial receptivity and embryo quality.

Phytoestrogens may improve the pregnancy rate in in vitro fertilization-embryo transfer cycles: a prospective, controlled, randomized trial

OBJECTIVE

To compare the effectiveness of i.m. P and i.m. P plus oral phytoestrogens for luteal phase support in patients undergoing IVF-ET cycles.

DESIGN

Prospective, controlled, randomized trial.

SETTING

University Hospital, Perugia, Italy.

PATIENT(S)

Two hundred thirteen infertile patients undergoing IVF-ET were included in the study. The inclusion criteria were use of a GnRH agonist for pituitary down-regulation and age <40 years. The total number of cycles performed was 274.

INTERVENTION(S)

Patients were assigned to receive either i.m. P (50 mg daily) plus placebo or P (50 mg daily) plus phytoestrogen supplementation (1,500 mg daily) for luteal phase support starting from the evening of oocyte retrieval until either a serum pregnancy test result was negative or embryonic heartbeat was sonographically confirmed.

MAIN OUTCOME MEASURE(S)

The outcomes of IVF-ET were evaluated in both study groups in terms of implantation rate, biochemical pregnancy rate (PR), clinical PR, spontaneous abortion rate, and ongoing pregnancy/delivered rate.

RESULT(S)

Statistically significant higher values for implantation rate, clinical PR, and ongoing pregnancy/delivered rate were recorded in the patients who received P plus phytoestrogens for luteal phase support in comparison with patients receiving P and placebo.

CONCLUSION(S)

Although the results of this study encourage the use of phytoestrogens for luteal phase support in patients undergoing IVF-ET program, more studies are necessary to support the hypothesis that phytoestrogens have a beneficial effect in IVF cycles.

The midluteal decline in serum estradiol levels is drastic but not deleterious for implantation after in vitro fertilization and embryo transfer in patients with normal or high responses

OBJECTIVE

To determine the impact of the peak E(2) level and its midluteal decline on IVF-ET outcome in a group of normal- and high-responding patients.

DESIGN

Retrospective analysis of IVF-ET data.

SETTING

Tertiary-care, university-affiliated teaching hospital.

PATIENT(S)

A total of 100 patients aged </=38 years and receiving up to three embryos per transfer who underwent a similar standard controlled ovarian hyperstimulation for IVF-ET.

INTERVENTION(S)

Morning blood was collected on days 0 (hCG day), +9, and +14.

MAIN OUTCOME MEASURE(S)

Treatment cycle hormonal characteristics and percent midluteal E(2) decline in conception and nonconception cycles.

RESULT(S)

Among all cycles, a mean decline of 95.0% in serum E(2) was observed at the midluteal phase. No significant differences were found in various parameters comparing conception with nonconception cycles. Occurrence of conception did not correlate with the absolute E(2) level or with percent E(2) decline in good and high responders. Early spontaneous abortion occurred more frequently in high responders with >98% E(2) decline; however, the difference did not reach statistical significance.

CONCLUSION(S)

Multifactorial analysis refutes the negative role of supraphysiologic levels of E(2) on the day of hCG administration or its dramatic decline at the midluteal phase on the success rate after embryo transfer. A possibly increased rate of early spontaneous abortion in the high-response group warrants further verification.

Endometrial response to IVF hormonal manipulation: comparative analysis of menopausal, down regulated and natural cycles

BACKGROUND

Uterine luminal epithelial cell response to different hormonal strategies was examined to determine commonality when an endometrium attains a receptive, stimulated, morphological profile that may lead to successful implantation.

METHODS

Endometrial biopsies from 3 cohorts of patients were compared. The tissue samples taken from these patients were categorized into 8 different groups according to their baseline and the hormone regime used.

RESULTS

Pre-treatment natural cycle tissue was variable in appearance. Downregulation with a GnRH analogue tissue appeared menopausal in character. HRT after downregulation resulted in tissue uniformity. HRT in menopause resulted in a 'lush' epithelial surface. HST in the natural cycle improved the morphology with significant difference in secretion between the two regimes examined.

CONCLUSIONS

Down regulation plus HRT standardized surface appearance but tissue response is significantly different from the natural cycle, natural cycle plus HRT or menopause plus HRT. HRT in menopause reinstates tissue to a state similar to a natural cycle but significantly different from a natural cycle plus HST. HST with a natural cycle is similar to tissue from the natural cycle but significant differences reflect the influence of the particular hormones present (at any point) within the cycle.

Human chorionic gonadotropin combined with progesterone for luteal support improves pregnancy rate in patients with low late-midluteal estradiol levels in IVF cycles

PURPOSE

To investigate how late-midluteal estradiol levels relate to the pregnancy outcome in IVF cycles, and to assess whether human chorionic gonadotropin (hCG) for luteal support benefits the pregnancy outcome of patients with low late-midluteal estradiol levels.

METHODS

The pregnancy rate of 436 women undergoing first IVF cycles with long protocol and luteal support with progesterone alone were analyzed. Unsuccessful women with low late-midluteal estradiol levels (< 100 pg/mL) proceeded with the exploratory second IVF cycles where they were randomly given with either progesterone alone (P protocol) or hCG +progesterone (P+hCG protocol) for luteal support.

RESULTS

Pregnancy rate in women with low late-midluteal estradiol levels was significantly lower compared to that with medium (100-500 pg/mL) and high (> 500 pg/mL) levels (13.3, 26.8, and 36.3%, respectively). P+hCG protocol increased late-midluteal estradiol levels and produced a significantly higher pregnancy rate (31.7%) than P protocol (13.7%).

CONCLUSIONS

hCG in combination with progesterone for luteal support was suggested to benefit women undergoing IVF with low late-midluteal estradiol levels.

Manipulation of the follicular phase: Uterodomes and pregnancy - is there a correlation?

BACKGROUND: Manipulation of the follicular phase uterine epithelium in women undergoing infertility treatment, has not generally shown differing morphological effects on uterine epithelial characteristics using Scanning Electron Microscopy (SEM) and resultant pregnancy rates have remained suboptimal utilising these manipulations. The present study observed manipulation of the proliferative epithelium, with either 7 or 14 days of sequential oestrogen (E) therapy followed by progesterone (P) and assessed the appearance of pinopods (now called uterodomes) for their usefulness as potential implantation markers in seven women who subsequently became pregnant. Three endometrial biopsies per patient were taken during consecutive cycles: day 19 of a natural cycle - (group 1), days 11/12 of a second cycle after 7 days E then P - (group 2), and days 19/22 of a third cycle after 14 days E then P - (group 3). Embryo transfer (ET) was performed in a subsequent long treatment cycle (as per Group 3). RESULTS: Seven pregnancies resulted in seven viable births including one twins and one miscarriage. Analysis of the individual regimes showed 5 days of P treatment to have a higher correlation for uterodomes in all 3 cycles observed individually. It was also observed that all 7 women demonstrated the appearance of uterodomes in at least one of their cycles. CONCLUSIONS: We conclude that manipulation of the follicular phase by shortening the period of E exposure to 7 days, does not compromise uterine epithelial morphology and we add weight to the conclusion that uterodomes indicate a receptive endometrium for implantation.

A rapid decline in serum oestradiol concentrations around the mid-luteal phase had no adverse effect on outcome in 763 assisted reproduction cycles

Progesterone is essential in the luteal phase whereas luteal oestradiol may play only a permissive role on the endometrium. However, a rapid decline in oestradiol concentrations around the mid-luteal period may compromise the endometrial integrity leading to poor IVF outcomes. A retrospective analysis of 763 women aged <40 years undergoing their first IVF cycle and having < or =3 embryos replaced was undertaken. In cycles receiving human chorionic gonadotrophin (HCG) for luteal support, 25th, 50th and 75th centiles of the ratio of day-of-HCG oestradiol to mid-luteal oestradiol (oestradiol ratio) were 1.8, 2.8 and 5.0 respectively. Hormonal parameters were not different between pregnant and non-pregnant cycles. The outcomes were similar irrespective of the oestradiol ratio. Progesterone supplementation was used instead when the HCG oestradiol was >18 000 pmol/l or there were features of ovarian hyperstimulation syndrome. Pregnancy rates of these hyperstimulated cycles were 16.7 and 11.4% per cycle respectively when oestradiol ratio was < or =5.0 and >5.0. This difference did not reach statistical significance. Our results could not find an adverse outcome in cycles showing a rapid decline in oestradiol during the mid-luteal phase.

Estradiol supplementation during the luteal phase may improve the pregnancy rate in patients undergoing in vitro fertilization-embryo transfer cycles

OBJECTIVE

To evaluate the effect of adding E(2) to progestin supplementation during the luteal phase on pregnancy and implantation rates in patients undergoing IVF cycles.

DESIGN

Prospective, randomized study.

SETTING

An IVF unit in a university hospital.

PATIENT(S)

Patients who were undergoing IVF with controlled ovarian hyperstimulation using a GnRH analog and who had E(2)2,500 pg/dL at the time of hCG administration.

INTERVENTION(S)

Serum concentrations of E(2) and progesterone were measured in all patients on days 7, 10, and 12 after ET.

MAIN OUTCOME MEASURE(S)

The E(2) and progesterone profiles of the luteal phase and the pregnancy and implantation rates were documented. Data were analyzed for the entire study population and further stratified according to the GnRH analog protocol used (short or long).

RESULT(S)

Significantly higher E(2) levels were found during the luteal phase in the group that received E(2) supplementation. This effect was more pronounced in the patients who were treated with the long GnRH analog protocol. Significantly higher pregnancy and implantation rates were recorded in the patients who received E(2) supplementation and were treated with the long GnRH analog protocol.

CONCLUSION(S)

For patients who are treated with the long GnRH analog protocol for controlled ovarian hyperstimulation and for whom luteal support with hCG is contraindicated, the addition of E(2) to the progestin support regimen may have a beneficial effect on pregnancy and implantation rates.

Ratio of oestradiol concentration on the day of human chorionic gonadotrophin administration to mid-luteal oestradiol concentration is predictive of in-vitro fertilization outcome

The role of luteal oestradiol for successful implantation in humans seems to be permissive rather than obligatory. Few studies have attempted to clarify the role of early luteal oestradiol in in-vitro fertilization (IVF) outcome, whether peri-implantation oestradiol is predictive of successful IVF outcome. We retrospectively analysed 106 women undergoing 106 IVF/embryo transfer cycles. Only the first treatment cycle per patient was analysed. Peak oestradiol denoted the concentration on the day of human chorionic gonadotrophin (HCG) administration. Mid-luteal oestradiol was obtained 3 days after embryo transfer (8 days after HCG administration). A total of 44 pregnancies were noted (41.51%). There were no differences in age, cycle day 3 follicle stimulating hormone (FSH), peak oestradiol, number of retrieved oocytes, number of embryo transfers, and mid-luteal oestradiol between pregnant and non-pregnant women. However, the ratio of day of HCG oestradiol to mid-luteal oestradiol was highly predictive of successful outcome: the ongoing pregnancy rate and implantation rate (sacs with fetal heart beat/embryo transfer) were 15.8 and 5.7% respectively if the above ratio exceeded 5.0 (n = 19), compared to 42.1 and 16.3%, and 53.3 and 26. 5% if the ratio was between 0.4 and 2.5 (n = 57), and between 2.5 and 5.0 (n = 30) respectively. Our study suggests that the magnitude of decline in oestradiol concentrations after oocyte retrieval may be important in predicting IVF success. We postulate that endometrial integrity may become compromised when a dramatic drop in oestradiol occurs by the mid-luteal period. Whether these women benefit from oestradiol supplementation after oocyte retrieval remains to be investigated.

17Beta-estradiol potentiates the stimulatory effects of progesterone on cadherin-11 expression in cultured human endometrial stromal cells

Cadherin-11 (cad-11) is a novel member of the cadherin gene superfamily of calcium-dependent cell adhesion molecules. To date, the factors capable of regulating this cell adhesion molecule remain poorly characterized. We have recently determined that cad-11 expression in the human endometrium is tightly regulated during the menstrual cycle. The spatiotemporal expression of cad-11 in the stromal cells of the human endometrium during the menstrual cycle suggests that gonadal steroids regulate the expression of this endometrial cell adhesion molecule. In view of these observations, we have examined the ability of progestins, estrogens, and androgens, alone or in combination, to regulate cad-11 expression in isolated human endometrial stromal cells using Northern and Western blot analyses. In these studies, we have determined that progesterone, but not 17beta-estradiol or dihydrotestosterone, is capable of regulating cad-11 messenger RNA and protein expression levels in isolated endometrial stromal cells. In addition, 17beta-estradiol, but not dihydrotestosterone, was capable of potentiating the stimulatory effects of progesterone in a dose-dependent manner. Taken together, these observations suggest that both 17beta-estradiol and progesterone are required for maximal cad-11 expression in human endometrial stromal cells in vitro.

Endometrial preparation: lessons from oocyte donation

OBJECTIVE

To gain insight into the physiology of human endometrial development after artificial preparation with estrogen (E) and P, before oocyte donation.

DESIGN

Review and analysis of relevant studies published in the last decade, identified through the literature and Medline searches.

RESULTS

Oocyte donation represents a unique in vivo experimental model in the human that permits the study of endometrial development under controlled variable conditions. Early studies have shown that adequate endometrial preparation can be achieved by sequential E and P only. The successful implementation of the simplified approach to oocyte donation demonstrated that satisfactory endometrial receptivity is not dependent on incremental administration of E and P and similarly can be achieved by fixed dosages of these steroids. Moreover, numerous clinical oocyte donation studies have shown that both physiologic and supraphysiologic levels of E and P have resulted in good endometrial development and pregnancy rates, underlining the relative insensitivity of the endometrium to extreme hormonal conditions. In addition, it has been clarified that the endometrium is tolerant of some manipulations during the follicular phase. Contrary to morphological studies that demonstrated preservation of endometrial preparation after luteal E depletion, preliminary evidence suggests that the functional capacity of the endometrium could be affected adversely.

CONCLUSION

In contrast to early oocyte donation studies, which indicated a correlation between morphologic integrity and functional capacity of the endometrium, some evidence presented in this review demonstrates that adequate endometrial morphology does not always imply normal endometrial receptivity.

Comparison of transdermal versus oral estradiol on endometrial receptivity

OBJECTIVE

To compare the effects of oral micronized E2 with transdermal E2 on endometrial receptivity in women undergoing oocyte donation.

DESIGN

Prospective, randomized, crossover trial. Serum E2 and P concentrations were measured on cycle days 14 and 22 (luteal day +8). Endometrial biopsies were obtained on day 22 and read in a blinded fashion for histology and beta-3-integrin expression.

SETTING

University-based donor oocyte program.

PATIENTS

Twenty-seven patients presenting for donor oocytes.

MAIN OUTCOME MEASURES

Endometrial histology and beta-3-integrin expression.

RESULTS

The endometrial glandular histology in women given oral micronized E2 was delayed by a mean of 1.6 days in comparison to that of women given transdermal E2. Seventy percent of women given oral E2 displayed a lag > or = 4 days whereas 29.6% given transdermal E2 displayed a similar lag. Serum E2 levels were 1,194 +/- 108.8 pg/mL (mean +/- SEM; conversion factor to SI unit, 3.671) in women on oral micronized E2 and 117.4 +/- 14.0 pg/mL in those on transdermal E2.

CONCLUSION

The supraphysiologic serum E2 levels associated with oral micronized E2 may have a deleterious impact on endometrial receptivity. The development of more physiologic hormone replacement protocols may enhance endometrial receptivity and lead to improved clinical pregnancy rates.