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BACKGROUND: The maximum daily dose of follitropin delta for ovarian stimulation in the first in vitro fertilization cycle is 12 µg (180 IU), according to the algorithm developed by the manufacturer, and based on patient's ovarian reserve and weight. This study aimed to assess whether 150 IU of menotropin combined with follitropin delta improves the response to stimulation in women with serum antimullerian hormone levels less than 2.1 ng/mL. METHODS: This study involved a prospective intervention group of 44 women who received 12 µg of follitropin delta combined with 150 IU of menotropin from the beginning of stimulation and a retrospective control group of 297 women who received 12 µg of follitropin delta alone during the phase 3 study of this drug. The inclusion and exclusion criteria and other treatment and follow-up protocols in the two groups were similar. The pituitary suppression was achieved by administering a gonadotropin-releasing hormone (GnRH) antagonist. Ovulation triggering with human chorionic gonadotropin or GnRH agonist and the option of transferring fresh embryos or using freeze-all strategy were made according to the risk of developing ovarian hyperstimulation syndrome. RESULTS: Women who received follitropin delta combined with menotropin had higher estradiol levels on trigger day (2150 pg/mL vs. 1373 pg/mL, p < 0.001), more blastocysts (3.1 vs. 2.4, p = 0.003) and more top-quality blastocysts (1.8 vs. 1.3, p = 0.017). No difference was observed in pregnancy, implantation, miscarriage, and live birth rates after the first embryo transfer. The incidence of ovarian hyperstimulation syndrome did not differ between the groups. However, preventive measures for the syndrome were more frequent in the group using both drugs than in the control group (13.6% vs. 0.6%, p < 0.001). CONCLUSIONS: In women with serum antimullerian hormone levels less than 2.1 ng/mL, the administration of 150 IU of menotropin combined with 12 µg of follitropin delta improved the ovarian response, making it a valid therapeutic option in situations where ovulation triggering with a GnRH agonist and freeze-all embryos strategy can be used routinely. TRIAL REGISTRATION: U1111-1247-3260 (Brazilian Register of Clinical Trials, available at https://ensaiosclinicos.gov.br/rg/RBR-2kmyfm ).
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Síndrome de Hiperestimulação Ovariana , Gravidez , Humanos , Feminino , Síndrome de Hiperestimulação Ovariana/epidemiologia , Síndrome de Hiperestimulação Ovariana/prevenção & controle , Síndrome de Hiperestimulação Ovariana/etiologia , Menotropinas , Estudos Prospectivos , Estudos Retrospectivos , Hormônio Antimülleriano , Taxa de Gravidez , Fertilização in vitro/métodos , Indução da Ovulação/métodos , Hormônio Liberador de GonadotropinaRESUMO
OBJECTIVE: Information on the pregnancy rate after successive in-vitro fertilization (IVF) cycles and their associated costs is relevant for couples undergoing assisted reproduction treatments (ARTs). This study, therefore, sought to investigate the effectiveness and the cost-effectiveness of two ARTs, the minimal ovarian stimulation IVF (MS-IVF) compared to the conventional ovarian stimulation IVF (C-IVF) from the payer's perspective. METHODS: A 10-months follow-up prospective observational study was conducted in a sample of couples who sought ARTs in a private clinic in Southern Brazil. Women had to satisfy the Bologna Criteria and be older than 35 years. The effect outcome was pregnancy rate per initiated cycle. Medication costs were based on medical records. Costs and effect differences were estimated using seemingly unrelated regressions adjusted for the propensity score estimated based on women's characteristics. RESULTS: All 84 eligible women who agreed to participate received a total of 92 IVF cycles (MS-IVF, n=27[35 cycles]; C-IVF n=57[57 cycles]. The effect difference between MS-IVF and C-IVF was -5.1% (95%CI, -13.2 to 5.2). Medication costs of MS-IVF were significantly lower than C-IVF by -1260 (95%CI, -1401 to -1118). The probabilities of MS-IVF being cost-effective compared to C-IVF ranged from 1 to 0.76 for willingness-to-pay of 0 to 15,000 per established pregnancy, respectively. CONCLUSIONS: Even though there were no positive effect differences between groups, MS-IVF might be cost-effective compared to C-IVF from the payer's perspective due to its relatively large cost savings compared to C-IVF. However, further investigation is needed to confirm these findings in a larger sample.
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Coeficiente de Natalidade , Fertilização in vitro , Gravidez , Feminino , Humanos , Análise Custo-Benefício , Pontuação de Propensão , Indução da Ovulação , FertilizaçãoRESUMO
OBJECTIVE: This paper aimed to assess the correlation between LH, LHR, GDF9, FSHR, AMH, AMHR2, and BMP15 polymorphisms, which are related to follicular development, and decreased ovarian response in women undergoing controlled ovarian hyperstimulation (COH) for IVF. METHODS: This age-matched case-control study included three or four controls per woman undergoing COH. Controls were women with normal ovarian response (NOR) and cases were women with poor ovarian response (POR) in oocyte retrieval (three or fewer oocytes). DNA was extracted from peripheral blood and potential associations with gene polymorphisms related to follicular development (LH, LHR, GDF9, FSHR, AMH, AMHR2, and BMP15) were analyzed. RESULTS: Sixty-six patients were included, 52 in the NOR and 14 in the POR group. Two GDF9 polymorphisms were associated with follicular response after COH, one associated with POR - the presence of a mutant polymorphism in heterozygosis and homozygosis of the GDF9 398-39 (C to G) [23% NOR versus 68% POR (OR 4.01, CI 1.52-10.6, p=0.005)] - and another associated with protective response - the presence of normal homozygosis of GDF9 (C447T) [19.2% NOR versus 50% POR (OR 0.34, IC 0.14-0.84, p=0.019)]. No additional associations were found between the other analyzed polymorphisms and POR. CONCLUSIONS: This study found that GDF9 appears to play an important role in follicular development, whereas polymorphisms in its DNA chain may negatively affect ovarian reserve, such as 398-39 (C to G), or positively, as seen in C447T.
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Fertilização in vitro , Reserva Ovariana , Proteína Morfogenética Óssea 15/genética , Estudos de Casos e Controles , Feminino , Fator 9 de Diferenciação de Crescimento/genética , Humanos , Ovário , Polimorfismo GenéticoRESUMO
Poor ovarian response remains one of the most challenging tasks for an IVF clinician. In this review, we aim to highlight the ongoing research for optimizing the prognosis in poor ovarian response patients. The newly introduced POSEIDON criteria argue that the first step is to move from a poor response to a poor prognosis concept, while improving identification and stratification of the different sub-types of poor prognosis patients prior to ovarian stimulation. The immediate marker of success is the ability of the ovarian stimulation to retrieve the number of oocytes needed to obtain at least one euploid blastocyst for transfer in each patient. This surrogate marker of success should not replace live birth as the most important outcome, but it should be approached as a useful tool for clinicians to evaluate their strategy for achieving live birth in the shortest timespan possible in the individual patient/ couple.
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Fertilização in vitro , Indução da Ovulação , Feminino , Humanos , Nascido Vivo , Ovário , Gravidez , PrognósticoRESUMO
STUDY QUESTION: Are cumulative and live birth rates (LBRs) comparable in poor ovarian response women treated with different protocols of mild stimulation IVF (i.e. oral compounds, lower doses or shorter treatments) versus conventional IVF? SUMMARY ANSWER: Mild ovarian stimulation (MOS) results in comparable outcomes to those of conventional stimulation in poor ovarian response patients with low ovarian reserve. WHAT IS KNOWN ALREADY: Several randomized trials and meta-analyses have been published evaluating the role of mild (MOS) versus conventional ovarian stimulation in poor ovarian response patients. Most report a potentially higher safety profile, patient satisfaction and lower costs, suggesting that the higher cycle cancellation rate and fewer oocytes retrieved following MOS does not affect the final reproductive outcome. Additionally, over the last few years, new publications have added data regarding MOS, and shown the possible benefit of a higher oocyte yield which may also improve prognosis in patients with poor ovarian response. STUDY DESIGN SIZE DURATION: We conducted a systematic search of relevant randomized controlled trials (RCTs). We searched electronic databases, including MEDLINE, EMBASE, LILACS-BIREME, CINAHL, The Cochrane Library, CENTRAL (Cochrane Register), Web of Science, Scopus, Trip Database and Open Grey, to identify all relevant studies published up to March 2020. We examined trial registries for ongoing trials. No publication-year or language restrictions were adopted. We explored the reference list of all included studies, reviews and abstracts of major scientific meetings. The primary outcomes were cumulative and fresh LBR (CLBR and FLBR) per woman randomized. PARTICIPANTS/MATERIALS SETTING METHODS: We included subfertile women undergoing IVF/ICSI characterized as poor responders and compared primary and secondary outcomes between the different protocols of mild stimulation IVF (i.e. oral compounds, lower doses or shorter treatments) and conventional IVF. We used the PICO (Patients, Intervention, Comparison and Outcomes) model to select our study population. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, 15 RCTs were included in the meta-analysis. CLBR and FLBR were comparable between mild versus conventional stimulation (RR 1.15; 95% CI: 0.73 - 1.81; I2 = 0%, n = 424, moderate certainty and RR 1.01; 95% CI: 0.97 - 1.04; I 2 = 0%, n = 1001, low certainty, respectively). No difference was observed either when utilizing oral compounds (i.e. letrozole and clomiphene) or lower doses. Similarly, ongoing pregnancy rate (OPR) and clinical pregnancy rate (CPR) were equivalent when comparing the two groups (RR 1.01; 95% CI: 0.98 - 1.05; I 2 = 0%, n = 1480, low certainty, and RR 1.00; 95% CI: 0.97 - 1.03; I2 = 0%, n = 2355, low certainty, respectively). A significantly lower oocyte yield (mean differences (MD) -0.80; 95% CI: -1.28, -0.32; I2 = 83%, n = 2516, very low certainty) and higher rate of cycle cancellation (RR 1.48; 95% CI: 1.08 - 2.02; I2 = 62%, n = 2588, low certainty) was observed in the MOS group. LIMITATIONS REASONS FOR CAUTION: The overall quality of the included studies was low to moderate. Even though strict inclusion criteria were used, the selected studies were heterogeneous in population characteristics and treatment protocols. We found no differences in CLBR between MOS and COS (95% CI: 0.73 - 1.81.). WIDER IMPLICATIONS OF THE FINDINGS: MOS could be considered as a treatment option in low prognosis poor responder patients, given that it results in similar fresh and CLBRs compared with COS. A milder approach is associated with a lower number of oocytes retrieved and a higher cancellation rate, although treatment cost is significantly reduced. Future research should focus on which type of ovarian stimulation may be of benefit in better prognosis women. STUDY FUNDING/COMPETING INTERESTS: There were no sources of financial support. N.P.P. received research grants, honoraria for lectures from: Merck Serono, MSD, Ferring Pharmaceuticals, Besins International, Roche Diagnostics, IBSA, Theramex and Gedeon Richter. P.D. received unrestricted grants and honoraria from Merck Serono, MSD and Ferring Pharmaceuticals. I.G.F. received unrestricted grants and honoraria from Merck Serono, MSD, Ferring Pharmaceuticals, Gedeon-Richter and IBSA. P.M.B. reported no conflict of interest. TRIAL REGISTRATION NUMBER: CRD42020167260.
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BACKGROUND: To determine if a modified ovarian sensitivity index (MOSI), based on initial follicular measurements and the initial follicle-stimulating hormone (FSH) dose, can predict the production of high-quality embryos for successful implantation during in vitro fertilization (IVF). METHODS: This study consisted of two phases: 1) a retrospective study and 2) a prospective observational study. For the first phase, 363 patients charts were reviewed, of which 283 had embryos transferred. All women underwent a standardized antagonist-based IVF protocol. At the first follow-up (Day 3/4), the number and size of the follicles were determined. MOSI was calculated as ln (number follicles (≥6 mm) × 1000 / FSH initial dose). Afterward, the number and quality of the ova, embryo development, and the number and quality of the blastocysts were determined. Embryo implantation was confirmed by ß-hCG. For the second phase, 337 IVF cycles were followed to determine MOSI's accuracy. RESULTS: MOSI could predict the production of ≥4 high-quality embryos by Day 2 (AUC = 0.69, 95%CI:0.63-0.75), ≥2 blastocysts (AUC = 0.74, 95%CI:0.68-0.79), and ≥ 35% rate of blastocyst formation (AUC = 0.65, 95%CI:0.58-0.72). Using linear regression, MOSI was highly associated with the number of ova captured (ß = 5.15), MII oocytes (ß = 4.31), embryos produced (ß = 2.90), high-quality embryos (ß = 0.98), and the blastocyst formation rate (ß = 0.06, p < 0.01). Using logistic regression, MOSI was highly associated with achieving ≥4 high-quality embryos (odds ratio = 2.80, 95%CI:1.90-4.13), ≥2 blastocysts (odds ratio = 3.40, 95%CI:2.33-4.95), and ≥ 35% blastocysts formation rate (odds ratio = 1.96, 95%CI:1.31-2.92). This effect was independent of age, BMI, and antral follicle count. For implantation, MOSI was significantly associated with successful implantation (odds ratio = 1.79, 95%CI:1.25-2.57). For the prospective study, MOSI was highly accurate at predicting ≥6 high-quality embryos on Day 2 (accuracy = 68.5%), ≥6 blastocysts (accuracy = 68.0%), and a blastocyst formation rate of ≥35% (accuracy = 61.4%). CONCLUSION: MOSI was highly correlated with key IVF parameters that are associated with achieved pregnancy. Using this index with antagonist cycles, clinicians may opt to stop an IVF cycle, under the assumption that the cycle will fail to produce good blastocysts, preventing wasting the patient's resources and time.
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Hormônio Liberador de Gonadotropina/antagonistas & inibidores , Ovário/fisiologia , Indução da Ovulação/métodos , Adulto , Implantação do Embrião , Feminino , Fertilização in vitro , Humanos , Ovário/efeitos dos fármacos , Gravidez , Taxa de Gravidez , Estudos Prospectivos , Estudos Retrospectivos , Adulto JovemRESUMO
This article represents a viewpoint on the POSEIDON criteria by a group of clinicians and embryologists. Its primary objective is to contextualize the Poseidon criteria and their metric of success for the relevant Frontiers Research Topic "POSEIDON's Stratification of Low Prognosis Patients in ART: The WHY, the WHAT, and the HOW". "Low prognosis" relates with reduced oocyte number, which can be associated with low or sometimes a normal ovarian reserve and is aggravated by advanced female age. These aspects will ultimately affect the number of embryos generated and consequently, the cumulative live birth rate. The novel system relies on female age, ovarian reserve markers, ovarian sensitivity to exogenous gonadotropin, and the number of oocytes retrieved, which will both identify the patients with low prognosis and stratify such patients into one of four groups of women with "expected" or "unexpected" impaired ovarian response to exogenous gonadotropin stimulation. Furthermore, the POSEIDON group introduced a new measure of clinical success in ART, namely, the ability to retrieve the number of oocytes needed to obtain at least one euploid blastocyst for transfer in each patient. Using the POSEIDON criteria, the clinician can firstly identify and classify patients who have low prognosis in ART, and secondly, aim at designing an individualized treatment plan to maximize the chances of achieving the POSEIDON measure of success in each of the four low prognosis groups. The novel POSEIDON classification system is anticipated to improve counseling and management of low prognosis patients undergoing ART, with an expected positive effect on reproductive success and a reduction in the time to live birth.
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Patients with poor ovarian response (POR) to exogenous gonadotropins stimulation for assisted reproductive technology (ART) have decreased circulating androgens during spontaneous cycles. The Patient-Oriented Strategies Encompassing Individualized Oocyte Number (POSEIDON) is a 4-tier stratification of women with POR to controlled ovarian stimulation (COH) based on age and biomarkers of ovarian reserve has been proposed to maximize the clinical management of this group for ART. The aim of the present study was to characterize the levels of androgens during COH in follicular fluid (FF) and serum in POSEIDON subgroups and compared them with women of normal ovarian response. Sixty nine consecutive patients undergoing ART were included and testosterone, androstenedione, dehydroepiandrosterone sulfate (DHEA-S), estradiol, sex hormone-binding globulin (SHBG), and insulin-like growth factor 1 (IGF-1) were measured in serum and FF collected at the time of oocyte pick-up. The number of retrieved oocytes was registered for each patient for their allocation to the respective POSEIDON subgroup. The control group comprised 19 women and the POSEIDON group 1 (age < 35, normal ovarian reserve biomarkers) n = 14, group 2 (age ≥ 35, normal ovarian reserve biomarkers) n = 8, group 3 (age < 35, poor ovarian reserve biomarkers) n = 6 and group 4 (age ≥ 35, poor ovarian reserve biomarkers) n = 22. Serum levels of total testosterone, androstenedione and DHEA-S were not different in group 1 vs. control but significantly decreased in group 3 vs. control. DHEA-S in FF was also significantly decreased in group 3 vs. control. In addition, serum testosterone was decreased in groups 2 and 4 vs. control; and serum androstenedione and estradiol were reduced in group 4 vs. control. No differences were observed for estradiol, SHBG and IGF-1 in FF. Finally, a high correlation between serum and FF DHEA-S was observed when data from samples of all groups were pooled. Group 1 did not show hypoandrogenemia however group 3 had low levels of all measured androgens in serum and DHEA-S in FF. Such differences might help to better characterize and/or improve the clinical management of women with POR according to their respective POSEIDON stratification.
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Women with impaired ovarian reserve or poor ovarian response (POR) to exogenous gonadotropin stimulation present a challenge for reproductive specialists. The primary reasons relate to the still limited knowledge about the POR pathophysiology and the lack of practical solutions for the management of these conditions. Indeed, clinical trials using the current standards to define POR failed to show evidence in favor of a particular treatment modality. Furthermore, critical factors for reproductive success, such as the age-dependent embryo aneuploidy rates and the intrinsic ovarian resistance to gonadotropin stimulation, are not taken into consideration by the current POR criteria. As a result, the accepted definitions for POR have been criticized for their inadequacy concerning the proper patient characterization and for not providing clinicians a guide for therapeutic management. A novel system to classify infertility patients with "expected" or "unexpected" inappropriate ovarian response to exogenous gonadotropins-the POSEIDON criteria-was developed to provide a more nuanced picture of POR and to guide physicians in the management of such patients. The new standards are provoking as they challenge the current terminology of POR in favor of the newly defined concept of "low prognosis." This article provides readers a critical appraisal of the existing criteria that standardize the definition of POR and explains the primary reasons for the development of the POSEIDON criteria.
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The aim of this review is to determine if the use of DHEA increases the likelihood of success in patients with POR. We searched MEDLINE and EMBASE using the terms "DHEA and diminished ovarian reserve", "DHEA and poor response", "DHEA and premature ovarian aging". A fixed effects model was used and Peto's method to get the odds ratio (OR) with 95% confidence intervals (CI 95%). For quantitative variables, Cohen's method was used to present the standardized mean differences (SMD) with their corresponding confidence intervals. Only five studied fulfilled the selection criteria. DHEA was administered in 25 mg doses, three times a day. In all studies, the authors corrected for the presence of confounding variables such as partner's age, infertility diagnosis and number of transferred embryos. The meta-analysis of the five selected studies assessed a total of 910 patients, who underwent IVF/ICSI, of which 413 had received DHEA. DHEA use was associated with a significant increase in pregnancy likelihood (OR 1.8, CI 95% 1.29 to 2.51, p=0.001). When analyzing the association between DHEA use and the likelihood of abortion, we found low heterogeneity between studies (I2=0.0%) and the use of DHEA to be associated to a significant reduction in the likelihood of abortion (OR 0.25, CI 0.07 to 0.95; p=0.045). Analysis of the association of DHEA with average oocyte retrieval showed high variability between studies (I2=98.6%), as well as no association between DHEA use and the number of oocytes retrieved (SMD -0.01, CI 95% -0.16 to 0.13; p<0.05).
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Desidroepiandrosterona/uso terapêutico , Fármacos para a Fertilidade Feminina/uso terapêutico , Fertilização in vitro , Reserva Ovariana , Adulto , Desidroepiandrosterona/administração & dosagem , Feminino , Fármacos para a Fertilidade Feminina/administração & dosagem , Humanos , Recuperação de Oócitos , Gravidez , Taxa de Gravidez , Injeções de Esperma Intracitoplásmicas , Resultado do TratamentoRESUMO
OBJECTIVE: To compare the clinical outcomes of follicular versus luteal phase ovarian stimulation in women with poor ovarian response (Bologna criteria) undergoing IVF. METHODS: This retrospective study investigated 446 patients submitted to 507 cycles in three groups. First, the two larger cohorts were examined: 154 patients treated with luteal phase ovarian stimulation (Group Lu); and 231 patients administered follicular phase ovarian stimulation (Group Fo). Then the clinical outcomes of 61 patients submitted to double ovarian stimulation were analyzed. Clinical outcomes included number of retrieved oocytes, fertilization rate, cleavage rate, top-quality embryo rate, clinical pregnancy rate (CPR), and live birth rate (LBR). RESULTS: Longer stimulation, higher dosages of HMG, and higher MII oocyte rates were achieved in Group Lu (p<0.001). There were no significant differences in CPR and LBR between the two groups offered frozen-thawed embryo transfer (28.4% vs. 33.0%, p=0.484; 22.9% vs. 25.5%, p=0.666). In the double ovarian stimulation group, the number of oocytes retrieved in the luteal phase stimulation protocol was higher (p=0.035), although luteal phase stimulation yielded a lower rate of MII oocytes (p=0.031). CPR and LBR were not statistically different (13.8% vs. 21.4%, p=0.525; 10.3% vs. 14.3%, p=0.706). CONCLUSION: Luteal phase ovarian stimulation may be a promising protocol to treat women with POR, particularly for patients unable to yield enough viable embryos through follicular phase ovarian stimulation or other protocols.
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Fase Luteal/fisiologia , Folículo Ovariano/fisiologia , Indução da Ovulação/métodos , Adulto , Coeficiente de Natalidade , Feminino , Humanos , Recuperação de Oócitos , Gravidez , Taxa de Gravidez , Estudos Retrospectivos , Fatores de Tempo , Resultado do TratamentoRESUMO
PURPOSE: The purpose of this study is to investigate the impact of follicular flushing on the number of oocytes retrieved, oocyte maturity, fertilization rate, embryo development, and pregnancy rate of poor ovarian responders (POR). METHODS: Retrospective study of 524 cycles of 384 patients with POR submitted to assisted reproductive technology (ART) and who had follicular flushing during oocyte retrieval was used in the study. We included patients with <5 oocytes at oocyte retrieval (POR group) and matching the Bologna criteria. RESULTS: POR patients had a mean age of 38.2 ± 4.2 years. A total of 1355 follicles (mean = 3.5 ± 1.6) were aspirated and 1040 oocytes recovered, with 709 (68.2%) obtained by direct aspiration and 331 (31.8%) by follicular flushing. We found a difference between the total number of oocytes and the number of aspirated oocytes. Overall pregnancy rate was 22%. Association was observed between pregnancy rate and the number of oocytes retrieved, the number of MII oocytes, and the number of embryos transferred. The patients matching the Bologna criteria had a mean age of 38.9 ± 3.9 years. A total of 309 follicles were aspirated (mean = 3.1 ± 1.5) and 242 oocytes recovered, with 156 (64.5%) obtained by direct aspiration and 86 (35.5%) by follicular flushing. There was a significant difference between the total number of oocytes and the number of aspirated oocytes. Overall pregnancy rate was 12.1%. There was no association between the pregnancy rate and the number of oocytes retrieved, the number of MII, and the number of embryos. CONCLUSIONS: Follicular flushing might be a suitable alternative to increase the number of oocytes and pregnancy rates in patients with POR.
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Recuperação de Oócitos/métodos , Indução da Ovulação/métodos , Adulto , Transferência Embrionária , Feminino , Fertilização in vitro , Humanos , Idade Materna , Folículo Ovariano/fisiologia , Gravidez , Taxa de Gravidez , Estudos Retrospectivos , Injeções de Esperma Intracitoplásmicas , Resultado do TratamentoRESUMO
OBJECTIVES: To examine whether endometrial thickness and the presence of endometrioma are independent predictors of clinical pregnancy rate or simply associated with poor ovarian response (POR). METHODS: This was a retrospective cohort study assessing the first cycle of all women undergoing in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) in a university hospital in Brazil between January 2011 and December 2012. Only the first cycle of each woman within the study period was considered. Women over 40 years of age and those who used clomiphene citrate during controlled ovarian stimulation (COS) or did not undergo embryo transfer were excluded from analysis. POR was defined as ≤ three oocytes retrieved and a thin endometrium was defined as endometrial thickness ≤ 7.0 mm on the day of human chorionic gonadotropin (hCG) administration. We performed a multiple regression analysis to identify which of the following parameters were independent predictors of clinical pregnancy: age, number of oocytes retrieved, endometrial thickness or the presence of endometrioma. RESULTS: Within the study period, 787 women began COS, but 270 were excluded from analysis. Among the 517 women analyzed, those who achieved pregnancy were younger and yielded more oocytes. The proportion of POR was higher in women with a thin endometrium (17/57 (29.8%) vs 80/460 (17.4%); P = 0.03) and in women with endometrioma (15/39 (38.5%) vs 82/478 (17.2%); P = 0.002). The results of regression analysis showed that only age and the number of oocytes retrieved were independent predictors of pregnancy. Additionally, we observed higher clinical pregnancy rates in women with a thin endometrium from whom ≥ seven oocytes were retrieved (11/25 (44.0%)) compared to women with normal endometrial thickness (99/241 (41.1%)). Considering only women from whom ≥ four oocytes were retrieved, we observed reasonable pregnancy rates in those with a thin endometrium (14/40 (35.0%)) and in those with endometrioma (9/24 (37.5%)). CONCLUSION: Both a thin endometrium and the presence of endometrioma are associated with POR but are not important independent predictors of clinical pregnancy. Good pregnancy rates can be observed when these conditions are present in women with a good ovarian response.