Use of luteal estrogen supplementation in normal responder patients treated with fixed multidose GnRH antagonist: a prospective randomized controlled study

Combined use of oestradiol and progesterone to support luteal phase in antagonist intracytoplasmic sperm injection cycles of normoresponder women: a case-control study

We evaluated the effect of combined use of oral oestrogen (E2) and vaginal progesterone (P) to support luteal phase in antagonist intracytoplasmic sperm injection (ICSI) cycles. We analysed data from 176 patients who underwent ICSI cycles with antagonist protocol. P 90 mg vaginal gel once a day and micronised E2 of 4 mg/day, were started from the day of oocyte pick up and continued to the 12th day of embryo transfer. Group 1 (n = 79) patients received E2 + P for luteal phase support. In group 2 (n = 97) patients, only P 90 mg vaginal gel was used for luteal phase support. There were no significant differences between group 1 and group 2 patients in terms of clinical pregnancy rates (PRs) (26.58% vs. 20.62%, p = .352), early pregnancy loss rates (6.33% vs. 6.19%, p = .969), incidence of luteal vaginal bleeding (8.86% vs. 8.25%, p = .885) and implantation rates (22.8% vs. 16.9%, p = .298). In conclusion, our study showed no beneficial effect of addition of E2 to luteal phase support on clinical PR in antagonist IVF cycles.Impact statementWhat is already known on this subject? Luteal phase deficiency is defined as a disruption in progesterone and oestrogen production after ovulation. It is clear that, luteal phase supplementation to improve the outcomes in in vitro fertilisation (IVF) cycles is mandatory. As an iatrogenic complication of assisted reproductive technique, decreased luteal oestrogen and progesterone levels lead to decreased pregnancy rates (PRs) and implantation rates.What the results of this study add? In this study, we aimed to present the role of luteal phase oestrogen administration in GnRH antagonist cycles. A total of 176 cases received progesterone vaginal gel form for luteal phase support. Study group received 4 mg oral oestradiol hemihydrate in addition to progesterone. Compared to previous studies, our study consisted of larger number of patients and we used oestradiol through oral route. We found out that luteal oestradiol support did not improve the clinical PR.What the implications are of these findings for clinical practice and/or further research? Our study showed no beneficial effect of addition of oestradiol to luteal phase support on clinical PR in antagonist IVF cycles.

Plasmatic estradiol concentration in the mid-luteal phase is a good prognostic factor for clinical and ongoing pregnancies, during stimulated cycles of in vitro fertilization

Objective

To evaluate the predictive efficiency of serum estradiol (E₂) concentration in the mid-luteal phase regarding chemical, clinical, and ongoing pregnancies, in patients subjected to IVF/ICSI with fresh embryo transfer.

Methods

One hundred and forty-three patients undergoing IVF/ICSI met all the inclusion criteria for the present study. Most of the patients used antagonists, final maturation was achieved with recombinant chorionic gonadotrophin (HCG), and embryo transfer took place on days 3 to 5, but mostly on day 4. The luteal phase was supplemented with estradiol valerate 6 mg/day and vaginal micronized progesterone 600 mg/day. There was no exclusion of patients in the embryo transfer group due to age or ovarian reserve. All patients with estradiol and chorionic gonadotrophin (βHCG) dosage on the day of transfer, day 7, were included. We assessed the following variables, initially regarding age: number of eggs collected, formed embryos, embryos transferred, day of transfer, transfer type, estradiol and chorionic gonadotropin. Next, we evaluated these elements at three different ranges of estradiol concentrations (<200 pg/ml, 200-500 pg/ml, and >500 pg/ml), comparing these parameters in pregnant (P) and non-pregnant (NP) patients.

Results

Data analysis by age group in P and NP patients showed significant differences in the mean values of the variables E₂ and βHCG, TD7. Mean serum estradiol levels in P and NP in the three age groups were: <35years, 835/417 p=0.0006, 35-39 years 833/434 p=0.0118, >39 years, 841/394 p=0.0012. There was also a significant difference in pregnancy rates in the group >500 pg/ml of estradiol concentration (63.4%, p=0.0096). The likelihood of chemical and clinical abortions for the estradiol ranges were: 38.46%, involving the two first ranges versus 15.15% for a concentration >500 pg/ml, p=0.0412 and 5.26% for a concentration >900 pg/ml, p=0.0105. The Pearson correlation coefficient for HCG and estradiol was r = 0.5108.

Conclusion

This study showed the prognostic value of E₂ in the mid-luteal phase (TD7) for chemical, clinical, and ongoing pregnancies, and its concentration suggested that there is a moderately positive correlation with βHCG levels.

Estradiol use in the luteal phase and its effects on pregnancy rates in IVF cycles with GnRH antagonist: a systematic review

For all the steps of in vitro fertilization to occur successfully, factors such as the quality of retrieved oocytes and endometrial receptivity to the embryo must be ensured. Current studies have shown that endometrial receptivity can be optimized using dedicated exogenous progesterone for luteal phase support in assisted reproduction cycles. But it has not yet been established the benefits of additional use of estradiol in this support. Analyzing pituitary suppression protocols that employ GnRH antagonists, this review will address literature publications between the years 2000-2016, shedding light on this issue to answer questions about the benefits of supplementation.

Luteal phase support for assisted reproduction cycles

BACKGROUND

Progesterone prepares the endometrium for pregnancy by stimulating proliferation in response to human chorionic gonadotropin(hCG) produced by the corpus luteum. This occurs in the luteal phase of the menstrual cycle. In assisted reproduction techniques(ART), progesterone and/or hCG levels are low, so the luteal phase is supported with progesterone, hCG or gonadotropin-releasing hormone (GnRH) agonists to improve implantation and pregnancy rates.

OBJECTIVES

To determine the relative effectiveness and safety of methods of luteal phase support provided to subfertile women undergoing assisted reproduction.

SEARCH METHODS

We searched databases including the Cochrane Menstrual Disorders and Subfertility Group (MDSG) Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO and trial registers. We conducted searches in November 2014, and further searches on 4 August 2015.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of luteal phase support using progesterone, hCG or GnRH agonist supplementation in ART cycles.

DATA COLLECTION AND ANALYSIS

Three review authors independently selected trials, extracted data and assessed risk of bias. We calculated odds ratios (ORs) and 95%confidence intervals (CIs) for each comparison and combined data when appropriate using a fixed-effect model. Our primary out come was live birth or ongoing pregnancy. The overall quality of the evidence was assessed using GRADE methods.

MAIN RESULTS

Ninety-four women RCTs (26,198 women) were included. Most studies had unclear or high risk of bias in most domains. The main limitations in the evidence were poor reporting of study methods and imprecision due to small sample sizes.1. hCG vs placebo/no treatment (five RCTs, 746 women)There was no evidence of differences between groups in live birth or ongoing pregnancy (OR 1.67, 95% CI 0.90 to 3.12, three RCTs,527 women, I2 = 24%, very low-quality evidence, but I2 of 61% was found for the subgroup of ongoing pregnancy) with a random effects model. hCG increased the risk of ovarian hyperstimulation syndrome (OHSS) (1 RCT, OR 4.28, 95% CI 1.91 to 9.6, low quality evidence).2. Progesterone vs placebo/no treatment (eight RCTs, 875 women)Evidence suggests a higher rate of live birth or ongoing pregnancy in the progesterone group (OR 1.77, 95% CI 1.09 to 2.86, five RCTs, 642 women, I2 = 35%, very low-quality evidence). OHSS was not reported.3. Progesterone vs hCG regimens (16 RCTs, 2162 women)hCG regimens included comparisons of progesterone versus hCG and progesterone versus progesterone + hCG. No evidence showed differences between groups in live birth or ongoing pregnancy (OR 0.95, 95% CI 0.65 to 1.38, five RCTs, 833 women, I2 = 0%, low quality evidence) or in the risk of OHSS (four RCTs, 615 women, progesterone vs hCG OR 0.54, 95% CI 0.22 to 1.34; four RCTs,678 women; progesterone vs progesterone plus hCG, OR 0.34, 95% CI 0.09 to 1.26, low-quality evidence).4. Progesterone vs progesterone with oestrogen (16 RCTs, 2577 women)No evidence was found of differences between groups in live birth or ongoing pregnancy (OR 1.12, 95% CI 0.91 to 1.38, nine RCTs,1651 women, I2 = 0%, low-quality evidence) or OHSS (OR 0.56, 95% CI 0.2 to 1.63, two RCTs, 461 women, I2 = 0%, low-quality evidence).5. Progesterone vs progesterone + GnRH agonist (seven RCTs, 1708 women)Live birth or ongoing pregnancy rates were lower in the progesterone-only group and increased in women who received progester one and one or more GnRH agonist doses (OR 0.62, 95% CI 0.48 to 0.81, nine RCTs, 2861 women, I2 = 55%, random effects, low quality evidence). Statistical heterogeneity for this comparison was high because of unexplained variation in the effect size, but the direction of effect was consistent across studies. OHSS was reported in one study only (OR 1.00, 95% CI 0.33 to 3.01, 1 RCT, 300 women, very low quality evidence).6. Progesterone regimens (45 RCTs, 13,814 women)The included studies reported nine different comparisons between progesterone regimens. Findings for live birth or ongoing pregnancy were as follows: intramuscular (IM) versus oral: OR 0.71, 95% CI 0.14 to 3.66 (one RCT, 40 women, very low-quality evidence);IM versus vaginal/rectal: OR 1.24, 95% CI 1.03 to 1.5 (seven RCTs, 2309 women, I2 = 71%, very low-quality evidence); vaginal/rectal versus oral: OR 1.19, 95% CI 0.83 to 1.69 (four RCTs, 857 women, I2 = 32%, low-quality evidence); low-dose versus high-dose vaginal: OR 0.97, 95% CI 0.84 to 1.11 (five RCTs, 3720 women, I2 = 0%, moderate-quality evidence); short versus long protocol:OR 1.04, 95% CI 0.79 to 1.36 (five RCTs, 1205 women, I2 = 0%, low-quality evidence); micronised versus synthetic: OR 0.9, 95%CI 0.53 to 1.55 (two RCTs, 470 women, I2 = 0%, low-quality evidence); vaginal ring versus gel: OR 1.09, 95% CI 0.88 to 1.36 (oneRCT, 1271 women, low-quality evidence); subcutaneous versus vaginal gel: OR 0.92, 95% CI 0.74 to 1.14 (two RCTs, 1465 women,I2 = 0%, low-quality evidence); and vaginal versus rectal: OR 1.28, 95% CI 0.64 to 2.54 (one RCT, 147 women, very low-quality evidence). OHSS rates were reported for only two of these comparisons: IM versus oral, and low versus high-dose vaginal. No evidence showed a difference between groups.7. Progesterone and oestrogen regimens (two RCTs, 1195 women)The included studies compared two different oestrogen protocols. No evidence was found to suggest differences in live birth or ongoing pregnancy rates between a short and a long protocol (OR 1.08, 95% CI 0.81 to 1.43, one RCT, 910 women, low-quality evidence) or between a low dose and a high dose of oestrogen (OR 0.65, 95% CI 0.37 to 1.13, one RCT, 285 women, very low-quality evidence).Neither study reported OHSS.

AUTHORS' CONCLUSIONS

Both progesterone and hCG during the luteal phase are associated with higher rates of live birth or ongoing pregnancy than placebo.The addition of GnRHa to progesterone is associated with an improvement in pregnancy outcomes. OHSS rates are increased with hCG compared to placebo (only study only). The addition of oestrogen does not seem to improve outcomes. The route of progester one administration is not associated with an improvement in outcomes.

Estrogen supplementation to progesterone as luteal phase support in patients undergoing in vitro fertilization: systematic review and meta-analysis

Meta-analyses have found conflicting results with respect to the use of progesterone or progesterone plus estrogen as luteal phase support for in vitro fertilization (IVF) protocols involving gonadotropins and/or gonadotropin-releasing hormone analogs. The aim of the present study was to perform an updated meta-analysis on the efficacy of progesterone versus progesterone plus estrogen as luteal phase support. We searched the MEDLINE, Cochrane Library, and Google Scholar databases (up to March 18, 2014). The search terms were (estrogen OR estradiol OR oestradiol) AND (progesterone) AND (IVF OR in vitro fertilization) AND (randomized OR prospective). We did not limit the form of estrogen and included subjects who contributed more than 1 cycle to a study. The primary outcome was clinical pregnancy rate. Secondary outcomes were ongoing pregnancy rate, fertilization rate, implantation rate, and miscarriage rate. A total of 11 articles were included in the present analysis, with variable numbers of studies assessing each outcome measure. Results of statistical analyses indicated that progesterone plus estrogen treatment was more likely to result in clinical pregnancy than progesterone alone (pooled odds ratio 1.617, 95% confidence interval 1.059-2.471; P = 0.026). No significant difference between the 2 treatment regimens was found for the other outcome measures. Progesterone plus estrogen for luteal phase support is associated with a higher clinical pregnancy rate than progesterone alone in women undergoing IVF, but other outcomes such as ongoing pregnancy rate, fertilization rate, implantation rate, and miscarriage rate are the same for both treatments.

Meta-analysis of estradiol for luteal phase support in in vitro fertilization/intracytoplasmic sperm injection

OBJECTIVE

To evaluate whether the addition of E(2) for luteal phase support (LPS) in IVF/intracytoplasmic sperm injection (ICSI) could improve the outcome of clinical pregnancy.

DESIGN

Meta-analysis.

SETTING

University hospital center.

PATIENT(S)

Women underwent IVF or ICSI using the GnRH agonist or GnRH antagonist protocol.

INTERVENTION(S)

Progesterone alone or combined with E(2) for LPS.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy rate per patient (CPR/PA), clinical pregnancy rate per ET, implantation rate, ongoing pregnancy rate per patient, clinical abortion rate, and ectopic pregnancy rate.

RESULT(S)

Fifteen relevant randomized controlled trials (RCTs) were identified that included a total of 2,406 patients. There was no statistical difference between E(2) + P group and P-only group regarding the primary outcome of CPR/PA for different routes of administration of E(2) (oral, vaginal, and transdermal) or other relevant outcome measures. No significant effect was observed for different daily doses of E(2) (6, 4, and 2 mg), even through oral medication in CPR/PA.

CONCLUSION(S)

The best available evidence suggests that E(2) addition during the luteal phase does not improve IVF/ICSI outcomes through oral medication, even with different daily doses. Furthermore, RCTs that study other administration routes are needed.

Which luteal phase support is better for each IVF stimulation protocol to achieve the highest pregnancy rate? A superiority randomized clinical trial

In vitro fertilization (IVF) cycles generate abnormalities in luteal-phase sex steroid concentrations and this represent an important limiting factor to achieve a good pregnancy rate. Although there are evidences about the usefulness of luteal phase support (LPS) after IVF cycles, no consensus exist about the best dose and way of progesterone (PG) administration, the advantages of estradiol (E2) supplementation and which IVF protocol could benefit from one more than other LPS scheme. Aim of the study was to assess the best LPS (low-dose PG, high-dose PG, high-dose PG and E2 supplementation) to achieve the highest clinical/ongoing pregnancy rate according to stimulation protocol, E2 at ovulation induction, endometrial thickness at pick-up and women's age. We conducted a randomized trial on 360 women undergoing IVF (180 treated by long-GnRH agonist, 90 by short-GnRH agonist and 90 by short-GnRH antagonist protocol) and stimulated by recombinant follicle-stimulating hormone alone. Our data demonstrated that high-dose PG is better than low-dose to increase both clinical and ongoing pregnancy rate. E2 supplementation are mandatory in case of short-GnRH antagonist protocol and strongly suggested in all protocols when E2max <5 nmol/l and endometrial thickness <10 mm. In long-GnRH agonist protocols, as well as in patients >35 years, the real advantages of E2 supplementation remain debatable and require further confirmation.

Assisted reproductive techniques

Assisted reproductive technologies (ART) encompass fertility treatments, which involve manipulations of both oocyte and sperm in vitro. This chapter provides a brief overview of ART, including indications for treatment, ovarian reserve testing, selection of controlled ovarian hyperstimulation (COH) protocols, laboratory techniques of ART including in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI), embryo transfer techniques, and luteal phase support. This chapter also discusses potential complications of ART, namely ovarian hyperstimulation syndrome (OHSS) and multiple gestations, and the perinatal outcomes of ART.

Luteal phase support for assisted reproduction cycles

BACKGROUND

Progesterone prepares the endometrium for pregnancy by stimulating proliferation in response to human chorionic gonadotropin (hCG), which is produced by the corpus luteum. This occurs in the luteal phase of the menstrual cycle. In assisted reproduction techniques (ART) the progesterone or hCG levels, or both, are low and the natural process is insufficient, so the luteal phase is supported with either progesterone, hCG or gonadotropin releasing hormone (GnRH) agonists. Luteal phase support improves implantation rate and thus pregnancy rates but the ideal method is still unclear. This is an update of a Cochrane Review published in 2004 (Daya 2004).

OBJECTIVES

To determine the relative effectiveness and safety of methods of luteal phase support in subfertile women undergoing assisted reproductive technology.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group (MDSG) Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO, CINAHL, Database of Abstracts of Reviews of Effects (DARE), LILACS, conference abstracts on the ISI Web of Knowledge, OpenSigle for grey literature from Europe, and ongoing clinical trials registered online. The final search was in February 2011.

SELECTION CRITERIA

Randomised controlled trials of luteal phase support in ART investigating progesterone, hCG or GnRH agonist supplementation in in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) cycles. Quasi-randomised trials and trials using frozen transfers or donor oocyte cycles were excluded.

DATA COLLECTION AND ANALYSIS

We extracted data per women and three review authors independently assessed risk of bias. We contacted the original authors when data were missing or the risk of bias was unclear. We entered all data in six different comparisons. We calculated the Peto odds ratio (Peto OR) for each comparison.

MAIN RESULTS

Sixty-nine studies with a total of 16,327 women were included. We assessed most of the studies as having an unclear risk of bias, which we interpreted as a high risk of bias. Because of the great number of different comparisons, the average number of included studies in a single comparison was only 1.5 for live birth and 6.1 for clinical pregnancy.Five studies (746 women) compared hCG versus placebo or no treatment. There was no evidence of a difference between hCG and placebo or no treatment except for ongoing pregnancy: Peto OR 1.75 (95% CI 1.09 to 2.81), suggesting a benefit from hCG. There was a significantly higher risk of ovarian hyperstimulation syndrome (OHSS) when hCG was used (Peto OR 3.62, 95% CI 1.85 to 7.06).There were eight studies (875 women) in the second comparison, progesterone versus placebo or no treatment. The results suggested a significant effect in favour of progesterone for the live birth rate (Peto OR 2.95, 95% CI 1.02 to 8.56) based on one study. For clinical pregnancy (CPR) the results also suggested a significant result in favour of progesterone (Peto OR 1.83, 95% CI 1.29 to 2.61) based on seven studies. For the other outcomes the results indicated no difference in effect.The third comparison (15 studies, 2117 women) investigated progesterone versus hCG regimens. The hCG regimens were subgrouped into comparisons of progesterone versus hCG and progesterone versus progesterone + hCG. The results did not indicate a difference of effect between the interventions, except for OHSS. Subgroup analysis of progesterone versus progesterone + hCG showed a significant benefit from progesterone (Peto OR 0.45, 95% CI 0.26 to 0.79).The fourth comparison (nine studies, 1571 women) compared progesterone versus progesterone + oestrogen. Outcomes were subgrouped by route of administration. The results for clinical pregnancy rate in the subgroup progesterone versus progesterone + transdermal oestrogen suggested a significant benefit from progesterone + oestrogen. There was no evidence of a difference in effect for other outcomes.Six studies (1646 women) investigated progesterone versus progesterone + GnRH agonist. We subgrouped the studies for single-dose GnRH agonist and multiple-dose GnRH agonist. For the live birth, clinical pregnancy and ongoing pregnancy rate the results suggested a significant effect in favour of progesterone + GnRH agonist. The Peto OR for the live birth rate was 2.44 (95% CI 1.62 to 3.67), for the clinical pregnancy rate was 1.36 (95% CI 1.11 to 1.66) and for the ongoing pregnancy rate was 1.31 (95% CI 1.03 to 1.67). The results for miscarriage and multiple pregnancy did not indicate a difference of effect.The last comparison (32 studies, 9839 women) investigated different progesterone regimens:intramuscular (IM) versus oral administration, IM versus vaginal or rectal administration, vaginal or rectal versus oral administration, low-dose vaginal versus high-dose vaginal progesterone administration, short protocol versus long protocol and micronized progesterone versus synthetic progesterone. The main results of this comparison did not indicate a difference of effect except in some subgroup analyses. For the outcome clinical pregnancy, subgroup analysis of micronized progesterone versus synthetic progesterone showed a significant benefit from synthetic progesterone (Peto OR 0.79, 95% CI 0.65 to 0.96). For the outcome multiple pregnancy, the subgroup analysis of IM progesterone versus oral progesterone suggested a significant benefit from oral progesterone (Peto OR 4.39, 95% CI 1.28 to 15.01).

AUTHORS' CONCLUSIONS

This review showed a significant effect in favour of progesterone for luteal phase support, favouring synthetic progesterone over micronized progesterone. Overall, the addition of other substances such as estrogen or hCG did not seem to improve outcomes. We also found no evidence favouring a specific route or duration of administration of progesterone. We found that hCG, or hCG plus progesterone, was associated with a higher risk of OHSS. The use of hCG should therefore be avoided. There were significant results showing a benefit from addition of GnRH agonist to progesterone for the outcomes of live birth, clinical pregnancy and ongoing pregnancy. For now, progesterone seems to be the best option as luteal phase support, with better pregnancy results when synthetic progesterone is used.

Luteal support: progestogens for pregnancy protection

Following ovulation, the granulosa cells undergo luteinization and form part of the corpus luteum; this then secretes progesterone that causes secretory transformation of the endometrium so that implantation can occur. The ideal time for implantation is 6-10 days after the luteinizing hormone (LH) surge; implantation occurring outside this optimal window is associated with a higher likelihood of miscarriage. Before the placenta takes over progesterone production, the progesterone produced by the corpus luteum also provides the necessary support to early pregnancy. A defect in corpus luteum function is not only associated with implantation failure but also with miscarriage. In assisted reproduction, both the use of gonadotropin-releasing hormone analogues to prevent the LH surge and aspiration of granulosa cells during the oocyte retrieval may impair the ability of the corpus luteum to produce sufficient progesterone. This may be treated effectively with progestational agents such as progesterone or dydrogesterone, which have a very similar pharmacological profile. Studies indicate that an estrogen may be given during the luteal phase to optimise the estrogen:progestogen ratio to facilitate implantation, although the available evidence is inconsistent in its strength for this hypothesis. In addition to assisted reproduction, progestational agents have shown beneficial effects in the management of patients with recurrent spontaneous miscarriage of unknown cause. In conclusion, despite the wide-spread use and many years of clinical experience, the amount of data from well-controlled clinical trials is currently limited. Further studies are therefore required to establish the optimal treatment situation and type and dose of progestational agent.

Does luteal estradiol supplementation have a role in long agonist cycles?

OBJECTIVE

To test the hypothesis that the addition of 6 mg estradiol (E2) valerate either orally or vaginally to progesterone (P) for luteal support, can increase the probability of pregnancy in intracytoplasmic sperm injection (ICSI) cycles using the long agonist protocol.

DESIGN

Prospective open-labeled randomized controlled trial.

SETTING

Private and university fertility centers.

PARTICIPANT(S)

Women undergoing ICSI cycles, with controlled ovarian hyperstimulation using long agonist protocol.

INTERVENTION(S)

On embryo transfer day, participants were randomized to receive, only P (group A, n = 90), P along with 6 mg E(2) valerate either orally (group B, n = 90), or vaginally (group C, n = 90) for luteal support.

MAIN OUTCOME MEASURE(S)

Clinical pregnancy was the main outcome. luteal serum E(2) and P profiles were the secondary outcomes.

RESULT(S)

Highest pregnancy rate was achieved in group C (45.56%), it was significantly higher than A (relative risk 1.52, 95% CI: 1.03 to 2.24). Day 0 (hCG day) E2 levels were similar in the three groups. Group A had lower E2 levels on days 7, 10, and 13 and a higher magnitude of E2 decline on days 7 and 10. Similar levels of luteal E2 were documented in groups B and C. P levels were similar in the three groups.

CONCLUSIONS(S)

Addition of 6 mg E(2) valerate to P support may encumber the sharp decline in luteal E(2) level. It may enhance the probability of pregnancy if administered vaginally.