Can serum oestradiol be a predictor of quality of oocytes and embryos, maturation of oocytes and pregnancy rate in ICSI cycles?

Effect of the ratios of estradiol increase on the outcome of in vitro fertilization-embryo transfer with antagonist regimens: a single center retrospective cohort study

BACKGROUND

The outcome of in vitro fertilization-embryo transfer (IVF) is often determined according to follicle and estradiol levels following gonadotropin stimulation. In previous studies, although most of them analyzed the estrogen level from ovaries or the average estrogen level of a single follicle, there was no study on the ratio of estrogen increase, which was also correlated with pregnancy outcomes in the clinic. This study aimed to make timely adjustments to follow-up medication to improve clinical outcomes based on the potential value of estradiol growth rate.

METHODS

We comprehensively analyzed estrogen growth during the entire ovarian stimulation period. Serum estradiol levels were measured on the day of gonadotropin treatment (Gn1), five days later (Gn5), eight days later (Gn8), and on the trigger day (HCG). This ratio was used to determine the increase in estradiol levels. According to the ratio of estradiol increase, the patients were divided into four groups: A1 (Gn5/Gn1 ≤ 6.44), A2 (6.44 < Gn5/Gn1 ≤ 10.62), A3 (10.62 < Gn5/Gn1 ≤ 21.33), and A4 (Gn5/Gn1 > 21.33); B1 (Gn8/Gn5 ≤ 2.39), B2 (2.39 < Gn8/Gn5 ≤ 3.03), B3 (3.03 < Gn8/Gn5 ≤ 3.84), and B4 (Gn8/Gn5 > 3.84). We analyzed and compared the relationship between data in each group and pregnancy outcomes.

RESULTS

In the statistical analysis, the estradiol levels of Gn5 (P = 0.029, P = 0.042), Gn8 (P < 0.001, P = 0.001), and HCG (P < 0.001, P = 0.002), as well as Gn5/Gn1 (P = 0.004, P = 0.006), Gn8/Gn5 (P = 0.001, P = 0.002), and HCG/Gn1 (P < 0.001, P < 0.001) both had clinical guiding significance, and lower one significantly reduced the pregnancy rate. The outcomes were positively linked to groups A (P = 0.036, P = 0.043) and B (P = 0.014, P = 0.013), respectively. The logistical regression analysis revealed that group A1 (OR = 0.376 [0.182-0.779]; P = 0.008*, OR = 0.401 [0.188-0.857]; P = 0.018*) and B1 (OR = 0.363 [0.179-0.735]; P = 0.005*, OR = 0.389 [0.187-0.808]; P = 0.011*) had opposite influence on outcomes.

CONCLUSION

Maintaining a serum estradiol increase ratio of at least 6.44 on Gn5/Gn1 and 2.39 on Gn8/Gn5 may result in a higher pregnancy rate, especially in young people.

S. L. Correlation between estradiol levels on day of HCG trigger and the number of mature follicles, number of oocytes retrieved, and the number of mature oocytes (M2) after oocyte aspiration in ICSI cycles

Background

Estradiol is an important marker of ovarian response to ovarian stimulation in ART cycles. The study tries to find the correlation of serum estradiol on the day of HCG trigger to the number of follicles, the number of oocytes retrieved, and the number of mature oocytes, and also, to correlate estradiol per follicle and estradiol per oocyte on the day of HCG, to the number of oocytes retrieved, and to the number of mature oocytes. It is a cross sectional study using retrospective data.

Results

The data of 232 patients were analyzed. Our study showed a positive correlation between estradiol levels and the number of follicles (NF) (r = 0.592, p < 0.001), number of retrieved oocytes (NRO) (r = 0.576, p < 0.001), and number of mature oocytes (NMO) (r = 0.554, p < 0.001). E/follicle ratio did not have a significant correlation with NRO and NMO. E/Oocyte ratio had a strong negative correlation with NMO (r = −0.280, p < 0.001)

Conclusions

Serum estradiol had a positive correlation with NF, NRO, and NMO. But E/O had a strong negative correlation with NMO. These results indicate that estradiol levels can be used as an important clinical tool in the prediction of oocyte and mature oocyte yield in ART cycles. Reproductive outcome in ART cycles is largely dependent on the number of oocytes and mature oocyte yield. Estradiol levels on the day of HCG appear to strongly correlate with the outcome of ART cycles.

The estradiol/oocyte ratio predicts the MII oocyte rate, but not live-birth rate in a depot gonadotropin-releasing hormone agonist long protocol

OBJECTIVE

To investigate whether the estradiol/oocyte ratio (E₂ /O) can predict ovarian response and pregnancy outcomes.

METHODS

This is a retrospective cohort study on 1838 individuals undergoing in vitro fertilization with a depot gonadotropin-releasing hormone agonist (GnRH-a) long protocol. The patients were grouped by the quartiles of E₂ /O: <131.2, 131.2-178.0, 178.0-242.9, and >242.9 pg/mL. ANOVA and χ² test with the Bonferroni adjustment were used for statistical analysis.

RESULTS

With the rise of E₂ /O, the MII oocyte rate increased, whereas the number of oocytes retrieved decreased. The number of MII oocytes, fertilization rate, and the number of high-grade embryos were similar among the four groups. There were no differences in live-birth rate, clinical pregnancy rate, ectopic pregnancy rate, and miscarriage rate, but there was a trend towards a higher miscarriage rate in the patients with E₂ /O between 131.2 and 242.9 pg/mL.

CONCLUSION

E₂ /O indicates the percentage of MII oocytes, but not the quality of an individual follicle. E₂ /O does not predict live birth in a depot GnRH-a long protocol; however, there is a trend towards a higher risk for miscarriage in the patients with E₂ /O between 131.2 and 242.9 pg/mL.

The association between treatment parameters on the day of gonadotropin-releasing hormone antagonist initiation during a flexible protocol and oocyte maturation rate

This study aimed to evaluate the effects of different treatment parameters on the day of GnRH antagonist initiation on oocyte maturation rate. We performed a retrospective cohort study of women aged ≤ 38 who underwent their first IVF-ICSI treatment using a flexible GnRH antagonist protocol in a single university-affiliated medical center during 2005-2015. Treatment parameters of three groups of oocyte maturation rates (<60%, 60-90%,>90%) were compared. Multivariate analysis was conducted to detect an association between treatment parameters on the day of GnRH antagonist initiation and oocyte maturation rate. The cohort included 458 patients, of whom 180 (39%) had a high oocyte maturation rate (≥90%), 211 (46%) had an oocyte maturation rate between 60-90% and 67 (15%) had a low maturation rate (≤60%). Women with a high maturation rate had longer duration of treatment (10.3 ± 2.9 days vs. 9.6 ± 2.5 vs. 9.5 ± 3.2, P = 0.019), lower levels of estradiol (1985 ± 1357 vs. 2406 ± 1666 vs. 2325 ± 1811, P = 0.027) and lower estradiol/maximal follicular diameter ratio on the day of GnRH antagonist initiation (137 ± 89 vs. 165 ± 103 vs. 163 ± 125, P = 0.019) as compared to women with medium and low maturation rates, respectively. Using linear regression multivariate analysis, lower estradiol and lower estradiol/maximal follicular diameter ratio on GnRH antagonist initiation day were associated with higher oocyte maturation rate. Further prospective studies to determine the best timing for GnRH antagonist initiation are needed.

Soluble LH-HCG receptor and oestradiol as predictors of pregnancy and live birth in IVF

RESEARCH QUESTION

Circulating soluble LH-HCG receptor (sLHCGR) is a first-trimester marker for screening pregnancy pathologies and predicts premature or multiple births before fertility treatment. Oestradiol per oocyte at ovulation induction predicts IVF treatment outcomes. We asked whether sLHCGR levels are stable during fertility treatment and whether, alone or with oestradiol, they could improve prediction of fertility treatment outcomes.

DESIGN

Serum sLHCGR, anti-Müllerian hormone [AMH] and oestradiol were measured in patients undergoing IVF. Antral follicle count before ovarian stimulation and oocyte yield were used to establish sLHCGR- oocyte ratio (SOR), sLHCGR- antral follicle ratio (SAR), oestradiol at trigger per oocyte (oestradiol-oocyte ratio [EOR]) and oestradiol at trigger per antral follicle (oestradiol-antral follicle ratio [EAR]).

RESULTS

The relatively stable sLHCGR was negatively related to AMH when oocyte yield was high. The sLHCGR levels were proportional (r = 0.49) to oestradiol at early cycle (day-3). Pregnancy and live birth were highest at low sLHCGR (≤1.0 pmol/ml) and SOR (≤ 0.1 pmol/ml/oocyte). A total of 86-89% of live births in IVF treatment were within the cut-off parameters of SAR and SOR (0.5 pmol/ml) and EAR and EOR (380 pg/ml). For failed pregnancy, age, SOR and EOR together had positive and negative predictive values of 0.841 and 0.703, respectively.

CONCLUSIONS

sLHCGR levels are negatively related to AMH when oocyte yield is high. High early cycle sLHCGR is associated with elevated day-3 oestradiol. Low sLHCGR and SOR are indicators of increased clinical pregnancy and live birth rates. Patient age and SOR, combined with EOR, might improve prediction of IVF treatment outcomes.

Relationship between a low ratio of serum estradiol to follicle number and fertility treatment outcomes: A retrospective cohort study of 516 cases

The aim of this retrospective study was to examine how a low estradiol/follicle (E2/fol) may be related to in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI)-embryo transfer outcomes in polycystic ovary syndrome (PCOS) and non-PCOS patients, respectively. Between 2013 and 2017, 516 IVF/ICSI cycles (146 cycles in PCOS patients and 370 cycles in non-PCOS patients) with a long gonadotrophin releasing hormone receptor agonist protocol-including 338 involved fresh transfer cycles (89 cycles in PCOS patients and 249 cycles in non-PCOS patients)-were conducted. Outcomes were compared between 5 groups of PCOS patients defined by E2/fol (pg/mL) as follows: A, <140; B, 140 to 210; C, 210 to 280; D, 280 to 350; and E, >350. Non-PCOS patients' outcomes are grouped as well. Whether in PCOS or non-PCOS patients, those in the lowest E2/fol group (<140 pg/mL) tended to be younger, and with a greater body mass index (BMI) and antral follicle count (AFC), than the patients in the other groups. Relative to the other groups, Group A showed a lower number and rate of oocytes, higher single pronucleus (1PN) and triple pronucleus (3PN) formation rate, early and advanced abortion rates, but these did not differ significantly from those of the other groups, it perhaps due to the limited sample size. Group A have a higher incidence of moderate or severe ovarian hyperstimulation syndrome than the other groups in non-PCOS patients (P > .05). Whether in PCOS or non-PCOS patients, greater BMI, greater AFC, and younger age may favor the phenomenon of low E2/fol. In turn, low E2/fol may reduce the oocyte retrieval rate and increase the risk of 1PN and 3PN formation and abortion.

The effects of low-dose human chorionic gonadotropin combined with human menopausal gonadotropin protocol on women with hypogonadotropic hypogonadism undergoing ovarian stimulation for in vitro fertilization

OBJECTIVES

To investigate the effects of low-dose human chorionic gonadotropin (hCG) combined with human menopausal gonadotropin (HMG) protocol on cycle characteristics and outcomes of infertile women with hypogonadotropic hypogonadism (HH) undergoing ovarian stimulation for in vitro fertilization (IVF).

DESIGN

A retrospective cohort study.

SETTING

Tertiary-care academic medical centre.

PATIENT(S)

Forty-six infertile patients with HH and seventy-one infertile patients with tubal factor (TF) infertility undergoing IVF.

INTERVENTION(S)

In the study group, all 46 HH patients were given low-dose hCG (50-300IU/d) in combination with HMG daily from cycle day 3. Meanwhile, a control group consisting of 71 patients with tubal factor infertility was set up, where the infertile women were given triptorelin 3.75 mg on cycle day 3 for desensitization and started stimulation with HMG only 5 weeks later. Transvaginal ultrasound and serum sex steroids were used for monitoring the development of follicles. Ovulation was triggered by hCG 5000IU when dominant follicles matured. Viable embryos were transferred on the third day after ovum pickup or cryopreserved for later transfer.

MAIN OUTCOME MEASURE(S)

The primary outcome measure was the clinical pregnancy rate. Secondary outcomes included hCG day P4, ratio of E2/follicle count, number of oocytes retrieved, number of viable embryos, implantation rate, ongoing pregnancy rate and cumulative pregnancy rate.

RESULT(S)

With lower basal FSH, LH and E2, HH patients showed longer HMG stimulation duration (13 (10-22) d vs 12 (8-18) d, P < .001) and higher HMG dose (2960 ± 560 IU vs 2663 ± 538 IU, P = .005). Whilst the antral follicle count (AFC), number of follicles with diameters greater than 10mm on trigger day and oocytes retrieved were less in the HH group, the number of follicles with diameters greater than 14 mm and viable embryos were comparable. The ratio of E2/follicle count (>10 mm) and E2/follicle count (>14 mm) were distinctively higher in the HH group (1056 ± 281 vs 830 ± 245, P < .001; 1545 ± 570 vs 1312 ± 594pmol/L, P = .037; respectively). The clinical pregnancy rate, implantation rate, ongoing pregnancy rate and cumulative pregnancy rate per woman were comparable between the two groups. Comparison among the subgroups with different hCG dosage showed that HMG duration shortened with the increase of daily hCG dose (14.84 ± 2.88 vs 13.96 ± 2.63 vs 12.96 ± 1.30 days, P = .037). No significant differences were detected in outcomes between fresh embryo transfer (ET) group and frozen-thawed embryo transfer (FET) group.

CONCLUSION(S)

Low-dose hCG combined with HMG is a feasible protocol for HH women undergoing ovarian stimulation in IVF, providing favourable cycle characteristics and pregnancy rates. Low-dose hCG reduces HMG duration, whilst the hCG dose and embryo quality are not positively correlated. The outcomes of FET are comparable to ET, which provides a greater chance of success from IVF in the low responders with HH.

Optimization of oestradiol assays to improve utility in an in vitro fertilization setting

Background The measurement of oestradiol is an integral component for the management of ovarian stimulation for in vitro fertilization. Automated immunoassays offer fast assay times and high throughput, with less sensitivity and specificity. The aim of this study is to optimize the oestradiol assay in patients undergoing ovarian stimulation for in vitro fertilization via comparison of oestradiol values obtained using two immunoassays compared with mass spectrometry. Methods Patients undergoing ovarian stimulation were prospectively recruited. Serum samples were analysed with ADVIA Centaur® CP Immunoassay, Abbott Architect i1000® immunoassay and AB Sciex 5500 liquid chromatography-tandem mass spectrometry (LC-MS/MS) systems. Per cent bias was determined for each system to report the average tendency of the values to be larger or smaller than the LC-MS/MS value. Linear regression of total follicular volume and oestradiol was computed. Results The ADVIA Centaur® CP assay had a positive bias of 20% compared with LC-MS/MS, while the Architect i1000® had a non-significant, negative bias of 0.3%. With regression fit, a clear, positive relationship was seen between follicular volume and oestradiol. The Architect i1000® assay had a greater correlation (R²= 0.46) compared with Centaur® CP (R²= 0.36), when oestradiol values were >1000 pg/mL (3670 pmol/L). Conclusions The Abbott Architect i1000® oestradiol assay exhibits greater agreement with LC-MS/MS and exhibited better correlation to follicular volume when oestradiol values are >1000 pg/mL (3670 pmol/L), prompting a change in the clinic's oestradiol platform. Attention to assay quality assurance via LC-MS/MS can improve the oestradiol accuracy and permit more informed clinical decisions for improved patient outcomes.

MicroRNA Profile of Granulosa Cells after Ovarian Stimulation Differs According to Maturity of Retrieved Oocytes

Background: Recent animal studies demonstrated that regulating the microRNA (miRNA) in granulosa cells (GCs) modulates the meiotic competence of oocytes. However, the difference in expression profiles of miRNAs in human GCs according to the maturity of the oocyte still remains to be elucidated. Objective: This observational study investigated whether the miRNA profile of human GCs differs according to the maturity of the retrieved oocyte after controlled ovarian stimulation for in vitro fertilization (IVF). Methods: Ten women who underwent ovarian stimulation cycles with GnRH agonist long protocols were recruited. The follicular fluid (FF) from dominant follicles was individually aspirated at oocyte retrieval. Oocytes were divided into two groups according to oocyte maturity ("mature group" vs. "immature group"). GCs were collected from the FF and miRNA was analyzed using real-time PCR. Results: Mean number of MII oocytes in the mature group was 1.6 ± 0.9 with none in the immature group (p = 0.008). Mean number of MI oocytes was 5.6 ± 2.1 in the mature group and 1.0 ± 0.0 in the immature group (p = 0.008). The total number of retrieved oocytes was 8.8 ± 1.9 in the mature group and 2.0 ± 1.2 in the immature group (p = 0.008). The GCs of the mature group showed a significantly lower expression of hsa-let-7b compared to the GCs of the immature group (p < 0.001). Conclusion: Taken together, the miRNA expression profiles of human GCs obtained from dominant follicles are associated with maturity of the adjacent oocyte and may be useful as a prognosticator of IVF outcome.

Serum estradiol:oocyte ratio as a predictor of reproductive outcome: an analysis of data from >9000 IVF cycles in the Republic of Ireland

PURPOSE

The purpose of this study was to evaluate the serum estradiol (E2) per oocyte ratio (EOR) as a function of selected embryology events and reproductive outcomes with IVF.

METHODS

This retrospective analysis included all IVF cycles where oocyte collection and fresh transfer occurred between January 2001 and November 2012 at a single institution. Patients were divided by three age groups (<35, 35-39, and ≥40 years) and further stratified into nine groups based on EOR (measured in pmol/L/oocyte). Terminal serum E2 (pmol/mL) was recorded on day of hCG trigger administration, and fertilization rate, cleavage rate, number of good quality embryos, and reproductive outcomes were recorded for each IVF cycle.

RESULTS

During the study interval, 9109 oocyte retrievals were performed for 5499 IVF patients (mean = 1.7 cycles/patient). A total of 63.4 % of transfers were performed on day 3 (n = 4926), while 36.6 % were carried out on day 5 (n = 2843). Clinical pregnancy rates were highest in patients with EOR of 250-750 and declined as this ratio increased, independent of patient age. While the odds ratio (OR) for clinical pregnancy where EOR = 250-750 vs. EOR > 1500 was 3.4 (p < 0.001; 95 % CI 2.67-4.34), no statistically significant correlation was seen in fertilization, cleavage rates or number of good quality embryos as a function of EOR.

CONCLUSIONS

Predicting reproductive outcomes with IVF has great utility both for patients and providers. The former have the opportunity to build realistic expectations, and the latter are better able to counsel according to measured clinical parameters. A better understanding of follicular dynamics and ovarian response to gonadotropin stimulation could optimize IVF treatments going forward.

Total fertilization failure: is it the end of the story?

PURPOSE

To study parameters that could predict in-vitro fertilization (IVF) success in patients who experienced total fertilization failure (TFF) with intracytoplasmic sperm injection (ICSI) in their previous cycles.

METHODS

Cycle characteristics of patients with TFF (Group I, n = 136 cycles), cycles resulting in embryo transfer (ET) following TFF (Group II, n = 36 cycles) and recurrent TFF (Group III, n = 25 cycles) and were studied retrospectively. Demographic features, cycle characteristics of three groups were compared.

RESULTS

Follicle count measuring 15-17 mm was significantly higher in group II when compared to group I (p = 0.02). Total number of retrieved oocytes and mature oocytes were significantly higher in group II when compared to groups I and III (p = 0.001). Estradiol level at oocyte pick up (OPU) day was significantly higher in group II when compared to group I (p = 0.02). When the characteristics of ET cycles and preceding TFF cycles of the same patient were compared, total number of retrieved oocytes (5.11 ± 0.72 (95% CI 3.69-6.52) vs. 11.44 ± 1.60 (95% CI 5.29-17.59)) and mature oocytes (3.26 ± 3.66 (95% CI 2.04-4.47) vs. 6.92 ± 5.61 (95% CI 5.09-8.75)) were found to be significantly lower in TFF cycles (p = 0.001). Five biochemical and 5 clinical pregnancies occurred while only 2 healthy babies were born, corresponding to a live birth rate 5.5%.

CONCLUSIONS

Increasing the number of retrieved and mature oocytes may increase the success of fertilization in patients with a history of previous failed fertilization. However, live birth rate is still low in embryo transfer cycles.

Serum estradiol as a predictor of success of in vitro fertilization

AIM

The aim of this study was to assess the role of total serum estradiol on the day of injection HCG, estradiol per mature follicle, and estradiol per oocytes retrieved (OR) on clinical pregnancy rate (CPR) and oocyte/embryo quality in assisted reproduction.

MATERIALS AND METHODS

A retrospective review of 342 in vitro fertilization cycles with normal ovarian reserve in women who underwent long GnRH agonist protocol was included. The outcomes assessed are number of OR, number of mature oocytes (MO), number of oocytes fertilized (FO), fertilization rate, number of embryos cleaved (EC), cleavage rate (CR), number of Grade I embryos (E), number of cryopreserved embryos (CPE), and CPR. The Estradiol/follicle ratio (E2/fol) was defined as estradiol level per mature follicle >14 mm in diameter. Estradiol/oocyte (E2/O) ratio was defined as estradiol level per OR. These two ratios were categorized by the 25th percentile into four groups.

RESULTS

A positive correlation was seen between E2/fol and OR (r = .334, p value = .0001), MO (r = .335, p value = .0001), FO (r = .222, p value = .002), and CPE (r = .289, p value = .0001). Increased CPR was seen in Group C (E2/fol = 200-299.99) compared to Group A, B, and D (p value = .033). With E2/O ratio, negative correlation was seen between E2/O and OR (r = -.281, p value = .002), MO (r = -.296, p value = .008), FO (r = -.220, p value = .003), EC (r = -.211, p value = .004), Grade 1 embryo (r = -.216, p value = .001), and CPE (r = -.206, p value = .005). No difference in FR, CR, or CPR was seen. No difference was seen in CPR with total serum estradiol.

CONCLUSIONS

In conclusion, serum estradiol is an important determinant of IVF success. While total serum estradiol does not exert any positive or negative influence on IVF outcome, estradiol per mature follicle and retrieved oocytes do have an impact. Pregnancy rate is better when E2/fol is between 200 and 299.99 pg/ml. Also, increasing serum E2/fol positively correlates with better oocytes and embryo quality. In contrast, E2/O negatively correlates with oocytes and embryo quality parameters.

The effect of cabergoline on folicular microenviroment profile in patients with high risk of OHSS

The aim of this study to evaluate the effect of cabergoline on follicular microenvironment by measuring follicular fluid (FF) insulin like growth hormone -I (IGF-I), antimullerian hormone (AMH), inhibin B and hepatocyte growth factor (HGF) levels in women with PCOS and high risk of ovarian hyperstimulation syndrome (OHSS). In this prospective cohort study, 41 women with PCOS undergoing controlled ovarian hyperstimulation for assisted reproduction and having the high risk factors for OHSS are included. The women in the study group (n = 15) received cabergoline for OHSS prevention while the women in the control did not received any medications for OHSS prevention. FF samples were collected during oocyte pick-up procedure for all women were determined using commercially available ELISA kits. Concentrations of FF IGF-I, AMH, inhibin B and HGF were assessed. In the study group FF AMH (2.96 ± 1.27 versus 1.91 ± 0.64 ng/mL), Inhibin B (1339.47 ± 198.56 versus 1200.09 ± 133.64 pg/mL), HGF (5623.21 ± 2411.09 versus 3787.42 ± 2269.89 pg/mL) and IGF-I (298.60 ± 37.80 versus 219.90 ± 71.40 pg/mL) concentrations were significantly decreased compared with control group. Cabergolin prevents OHSS in high risk patients by disrupting FF hormone microenvironment.

Does empty zona pellucida indicate poor ovarian response on intra cytoplasmic sperm injection cycles?

The factors behind the empty zona pellucida (EZP) formation and its relationship with in vitro fertilization (IVF) outcomes were analyzed. A total of 104 patients who underwent IVF treatment and collected oocytes including EZP were enrolled in this study. EZP index (EZPI = the ratio of number of EZP to number of cumulus-oocyte complex (COC)) was used for the statistical analysis. Patients were grouped as Group 1 when EZPI ≤ 0.17 (n = 57) and Group 2 when EZPI > 0.17 (n = 47). Type-2 EZP, a variation or an advanced type of oocyte degeneration, is tested. Woman age, basal hormone levels, and total gonadotropin dose were significantly higher in Group 2 compared to Group 1. Total antral follicle count was significantly low in Group 2. Total number of mature oocytes, oocyte quality index, the number of fertilized oocytes, and the numbers of Grade 1 embryos were significantly low in Group 2. On the linear regression analysis, using gonadotropin releasing hormone antagonist protocol (B = 0.086, p = 0.030), the number of ≥17 mm follicle (B = 0.015, p = 0.047), peak serum level of estradiol (B = -3.625; p = 0.014), number of fertilized oocytes (B = -0.02, p = 0.0001) and the day-2 embryo score (B = -0,044, p = 0.001) significantly affected EZPI. An increment of the EZPI may be revealed decreased oocyte quality, and it is also related to the poor ovarian response.