A critical review of bi-dimensional and three-dimensional ultrasound techniques to monitor follicle growth: do they help improving IVF outcome?

A follicular volume of >0.56 cm3 at trigger is the cutoff to predict oocyte maturity: a starting point for novel volume-based triggering criteria

OBJECTIVE

To determine the minimum follicular volume on the day of trigger that will correspond to a mature oocyte at egg retrieval by individualized follicular puncture and to calculate the mean follicular growth from ovulation induction to egg retrieval using SonoAVCfollicle.

DESIGN

A prospective observational study of 53 women undergoing in vitro fertilization, in which it was possible to identify unequivocally one or more follicles at trigger and egg retrieval using three-dimensional ultrasound.

SETTING

University-affiliated private in vitro fertilization center.

PATIENTS

The final sample included 206 follicles from 14 oocyte donors and 39 patients.

INTERVENTIONS

A three-dimensional ultrasound with SonoAVCfollicle was performed at trigger and egg retrieval. The same operator selected follicles that were identified easily on both scans and verified that they were apt to be aspirated individually. Follicles were punctured individually, recording the real aspirated volume and the maturity stage of the oocyte.

MAIN OUTCOME MEASURES

The primary outcome was the relationship between follicular volume on the day of the trigger and the oocyte maturity stage. The secondary outcome was the rate of follicular growth from the day of trigger to the day of oocyte retrieval, as measured using SonoAVCfollicle.

RESULTS

On the day of trigger 206, follicles were selected. Of these, 5 could not be identified on the day of oocyte retrieval, probably because of follicular rupture (mean volume: 4 cm3, range: 2-7 cm3), and in 48, an oocyte was not obtained. The relationship between follicular volume and oocyte maturity was studied in 153 follicles: 125 (82%) contained mature and 28 (18%) contained immature oocytes. Receiver operating characteristic curves showed an area under the curve value of 0.73 (95% confidence interval: 0.65-0.80). A follicular volume of >0.56 cm3 is the cutoff point, with the highest Youden index having a sensitivity of 85% and a specificity of 64% to predict oocyte maturity. The mean follicular growth from trigger to egg retrieval was 26%-50% in 53% of cases.

CONCLUSION

A follicular volume of >0.56 cm3 at trigger is the cutoff point with the optimal balance between sensitivity and specificity for oocyte maturity. Follicles of >2-3 cm3 may undergo spontaneous rupture before egg retrieval. Given these findings, we propose new volume-based criteria for trigger: 70% of follicles of >0.6 cm3 and dominant follicles between 2 and 3 cm3. These findings need validation by randomized controlled trials.

Effect of follicle size on pregnancy outcomes in patients undergoing first letrozole-intrauterine insemination

BACKGROUND

Letrozole has been proven to be an effective method for inducing ovulation. However, little attention has been paid to whether the lead follicle size will affect the success rate of intrauterine insemination (IUI) with ovulation induction with alone letrozole. Therefore, we hope to investigate the effect of dominant follicle size on pregnancy outcomes on human chorionic gonadotropin (hCG) day of the first letrozole-IUI.

METHODS

A retrospective cohort study design was employed. We included patients with anovulation or unexplained infertility undergoing first IUI treatment with letrozole for ovarian stimulation. According to the dominant follicle size measured on the day of hCG trigger, patients were divided into six groups (≤ 18 mm, 18.1-19.0 mm, 19.1-20.0 mm, 20.1-21.0 mm, 21.1-22.0 mm, > 22 mm). Logistic models were used for estimating the odds ratios (ORs) with their 95% confidence interval (CIs) for achieving a clinical pregnancy or a live birth. A restricted cubic spline was drawn to explore the nonlinear relationship between follicle size and IUI outcomes.

RESULTS

A total of 763 patients underwent first letrozole-IUI cycles in our study. Fisher exact test showed significant differences among the six follicle-size groups in the rates of pregnancy, clinical pregnancy and live birth (P < 0.05 in each group). After adjusting the potential confounding factors, compared with the follicles ≤ 18 mm in diameter group, 19.1-20.0 mm, 20.1-21.0 mm groups were 2.3 or 2.56 times more likely to get live birth [adjusted OR = 2.34, 95%CI (1.25-4.39); adjusted OR = 2.56, 95% CI (1.30-5.06)]. A restricted cubic spline showed an inverted U-shaped relationship between the size of dominant follicles and pregnancy rate, clinical pregnancy rate, and live birth rate, and the optimal follicle size range on the day of hCG trigger was 19.1-21.0 mm. When the E2 level on the day of hCG trigger was low than 200 pg/mL, the clinical pregnancy rates of 19.1-20.0 mm, 20.1-21.0 mm groups were still the highest.

CONCLUSIONS

The optimal dominant follicle size was between 19.1 and 21.0 mm in hCG-triggered letrozole-IUI cycles. Either too large or too small follicles may lead to a decrease in pregnancy rate. Using follicle size as a predicator of pregnancy outcomes is more meaningful when estrogen on the day of hCG trigger is less than 200 pg/ml.

A reappraisal of ovarian stimulation strategies used in assisted reproductive technology

Ovarian stimulation is a fundamental step in assisted reproductive technology (ART) with the intention of inducing ovarian follicle development prior to timed intercourse or intra-uterine insemination and facilitating the retrieval of multiple oocytes during a single in vitro fertilization (IVF) cycle. The basis of ovarian stimulation includes the administration of exogenous gonadotropins, with or without pre-treatment with oral hormonal therapy. Gonadotropin-releasing hormone agonist or antagonist is given in addition to the gonadotropins to prevent a premature rise of endogenous luteinizing hormone that would in turn lead to premature ovulation. With the advancement in technology, various stimulation protocols have been devised to cater for different patient needs. However, ovarian hyperstimulation syndrome and its serious complications may occur following ovarian stimulation. It is also evident that suboptimal ovarian stimulation strategies may have a negative impact on oogenesis, embryo quality, endometrial receptivity, and reproductive outcomes over recent years. This review describes the various forms of pre-treatment for ovarian stimulation and stimulation protocols, and aims to provide clinicians with the latest available evidence.

Impact of follicular size categories on oocyte quality at trigger day in young and advanced-age patients undergoing GnRH-ant therapy

Aim

To study the effect of follicle sizes of different proportions on oocyte and embryo quality in young and advanced-age patients, and provide evidence for personalized protocol adjustment.

Methods

This was a retrospective real-world data study including a total of 11,462 patients who had started their first in vitro fertilization cycle with a gonadotropin-releasing hormone antagonist (GnRH-ant) protocol during 2018-2021. We classified patients into groups according to the size of the dominant proportion of follicles on the human chorionic gonadotropin (hCG) trigger day: Large, Medium, Small, and Equal (containing equivalent proportions of all three size categories). The Cochran-Mantel-Haenszel test by different Anti-Mullerian Hormone (AMH) and antral follicle count (AFC) was used to compare factors such as the metaphase II (MII) oocyte rate, normal fertilization rate, and two pronuclei (2PN) cleavage rate between groups. General linear model (GLM) analysis was performed for inter-group comparison of the oocyte and embryo quality.

Results

In patients aged < 35 years and with AMH ≥ 1.2μg/L, the MII oocyte percentages in the Large and Medium groups were significantly higher than in the Small group (P < 0.001). The germinal vesicle (GV) oocyte and unavailable oocyte percentages in the Large and Medium groups were lower than in the Small group (P < 0.001). Among patients aged ≥ 35 years with AFC < 5 and AMH ≥ 1.2μg/L, the GV oocyte percentage in the Large group was significantly lower than in the Medium group (2.54% vs. 4.46%, P < 0.001). In patients < 35 years, the GLM demonstrated that the Large and Medium groups had positively impacted on the development of MII oocyte and live birth rate(LBR) of first embryo transfer(ET)(β>0, all P value < 0.05);and had less likely to develop into unavailable oocyte, degenerated oocyte, GV oocyte and MI oocyte rates relative to the Small group(β<0, all P value < 0.05). And among patients ≥ 35 years, the Medium group had positively impacted on the development of MII oocyte and 2PN rates relative to the Small group(β>0, all P value < 0.05); and had less likely to develop into MI oocytes relative to the Small group(β<0, all P value < 0.05). The GLM indicated that AMH, along with Gn total dose, start dose, and Gn days, had significant impact on oocyte and embryo quality. For young patients, age was not a significant influencing factor, but for advanced-age patients, age influenced the outcomes.

Conclusion

Our analysis suggests that for young patients (< 35 years), triggering when there is a high proportion of large or medium follicles results in better quality oocytes, while for older patients (≥ 35 years), it is better to trigger when the proportion of medium follicles is no less than that of small follicles. Further research is required to confirm these findings.

Triggering with 1,500 IU of human chorionic gonadotropin plus follicle-stimulating hormone compared to a standard human chorionic gonadotropin trigger dose for oocyte competence in in vitro fertilization cycles: a randomized, double-blinded, controlled noninferiority trial

OBJECTIVE

To assess if triggering with 1,500 IU of human chorionic gonadotropin (hCG) with 450 IU of follicle-stimulating hormone (FSH) induces noninferior oocyte competence to a standard dose of hCG trigger used in in vitro fertilization (IVF). The alternative trigger will be considered noninferior if it is at least 80% effective in promoting oocyte competence.

DESIGN

Randomized, double-blinded, controlled noninferiority trial.

SETTING

Academic infertility practice.

PATIENTS

Women aged 18-41 undergoing IVF with antral follicle count ≥8, body mass index ≤30 kg/m², and no history of ≥2 IVF cycles canceled for poor response were enrolled. Participants with a serum estradiol >5,000 pg/mL on the day of trigger were excluded because of high risk of ovarian hyperstimulation syndrome.

INTERVENTIONS

Participants were randomized to receive an alternative trigger of 1,500 IU of hCG plus 450 IU of FSH or a standard trigger dose of hCG (5,000 or 10,000 IU) for final oocyte maturation.

MAIN OUTCOME MEASURES

The primary outcome was total competent proportion, defined as the probability of 2 pronuclei from an oocyte retrieved. The alternative trigger will be considered noninferior to the standard trigger if a 1-sided 95% confidence interval (CI) of the relative risk (RR) is not <0.8. Secondary outcomes included oocyte recovery and maturity, intracytoplasmic sperm injection fertilization, embryo quality, pregnancy rates, as well as serum and follicular hormones. Secondary outcomes were compared using a 2-sided superiority test. Outcomes were analyzed by intention-to-treat and per-protocol.

RESULTS

A total of 105 women undergoing IVF were randomized from May 2015 to June 2018. The probability of the primary outcome was 0.59 with the alternative trigger and 0.65 with the standard trigger, with a RR of 0.91 and a 1-sided 95% CI of 0.83. Noninferiority of the alternative trigger was demonstrated. Live birthrate from all fresh transfers in the alternative trigger group vs. standard trigger was 46.9 vs. 46.4% (RR, 1.01; 95% CI, 0.62-1.62), respectively. Live birthrate per randomized participant was 48.1% in the alternative trigger group vs. 62.7% with the standard trigger (RR, 0.73; 95% CI, 0.48-1.11). No participants had a failed retrieval.

CONCLUSION

Triggering with 1,500 IU of hCG plus 450 IU of FSH promoted noninferior oocyte competence compared to a standard hCG trigger dose.

TRIAL REGISTRATION

NCT02310919.

An interpretable machine learning model for predicting the optimal day of trigger during ovarian stimulation

OBJECTIVE

To develop an interpretable machine learning model for optimizing the day of trigger in terms of mature oocytes (MII), fertilized oocytes (2PNs), and usable blastocysts.

DESIGN

Retrospective study.

SETTING

A group of three assisted reproductive technology centers in the United States.

PATIENT(S)

Patients undergoing autologous in vitro fertilization cycles from 2014 to 2020 (n = 30,278).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Average number of MII oocytes, 2PNs, and usable blastocysts.

RESULT(S)

A set of interpretable machine learning models were developed using linear regression with follicle counts and estradiol levels. When using the model to make day-by-day predictions of trigger or continuing stimulation, possible early and late triggers were identified in 48.7% and 13.8% of cycles, respectively. After propensity score matching, patients with early triggers had on average 2.3 fewer MII oocytes, 1.8 fewer 2PNs, and 1.0 fewer usable blastocysts compared with matched patients with on-time triggers, and patients with late triggers had on average 2.7 fewer MII oocytes, 2.0 fewer 2PNs, and 0.7 fewer usable blastocysts compared with matched patients with on-time triggers.

CONCLUSION(S)

This study demonstrates that it is possible to develop an interpretable machine learning model for optimizing the day of trigger. Using our model has the potential to improve outcomes for many in vitro fertilization patients.

Stimulation Duration in Patients with Early Oocyte Maturation Triggering Criteria Does Not Impact IVF-ICSI Outcomes

Results from studies reporting the optimal stimulation duration of IVF-ICSI cycles are inconsistent. The aim of this study was to determine whether, in the presence of early ovulation-triggering criteria, prolonged ovarian stimulation modified the chances of a live birth. This cross-sectional study included 312 women presenting triggering criteria beginning from D8 of ovarian stimulation. Among the 312 women included in the study, 135 were triggered for ovulation before D9 (D ≤ nine group) and 177 after D9 (D > nine group). The issues of fresh +/− frozen embryo transfers were taken into consideration. Cumulative clinical pregnancy and live-birth rates after fresh +/− frozen embryo transfers were similar in both groups (37% versus 46.9%, p = 0.10 and 19.3% versus 28.2%, p = 0.09, respectively). No patient characteristics were found to be predictive of a live birth depending on the day of ovulation trigger. Postponing of ovulation trigger did not impact pregnancy or live-birth rates in early responders. A patient’s clinical characteristics should not influence the decision process of ovulation trigger day in early responders. Further prospective studies should be conducted to support these findings.

Two novel mutations in exon 2 of bone morphogenetic protein (BMP) 15 gene in Pakistani infertile females

Objective

To determine the proportion of fertility in Pakistani infertile females and discover if there are considerable connection among BMP15 gene polymorphism, follicle maturation and hormonal regulation in Pakistani infertile females.

Methods

All selected participants were initially examined through follicle-stimulating hormones (FSH), luteinizing hormone (LH), thyroid-stimulating hormone (TSH), Prolactin, and Trans-vaginal scan (TVS). BMP15 gene polymorphism among infertile and fertile females was done by extracted Genomic DNA from whole blood. Sanger sequencing was performed for the identification of mutation in exons-intron boundaries of the BMP15 gene. Bioinformatics tools were used to assess the protein structure.

Results

The total five mutations including two novel missense variants of BMP15 in exon 2, whereas three previously reported i.e. two cosmic mutations (c.615delC), (c.584InsG) and one frame shift mutations (c.635delA) were also observed. The first novel mutation was found at (c.1038InsGG) (p.346Gln < Gly) in which the insertion of GG at DNA position 1038 of exon 2 resulting in a substitution of glutamine into glycine at 346th amino acid of BMP15 protein. The second novel variant (c.1049delT) (p. Ser334Pro) was also observed in exon 2 of the BMP15 gene, which substituted serine into proline at 334th amino acid of the BMP15 protein.

Conclusion

It is concluded that there are various missense mutations present in exon 2 of the BMP15 gene of Pakistani infertile females, consequently expected function of protein changes due to change in codons of amino acids. Provean and SIFT suggest the two novel variants as potentially deleterious. Although three other variants were also found in Pakistani infertile females which were previously reported. These mutations may result in early blockage of folliculogenesis and ovaries become streaky. Further research is required to resolve the actual allusion of these variations in the BMP15 gene.

Determining the optimal follicle size at trigger in patients undergoing ovarian stimulation with a clomiphene citrate plus gonadotropin and GnRH antagonist protocol for in vitro fertilization

OBJECTIVE

Determine the optimal follicle size at trigger in clomiphene citrate-based IVF protocols.

STUDY DESIGN

This is a retrospective cohort study performed in at a single academic institution that included first IVF cycles with clomiphene citrate-based protocols at our center between 01/01/2013-03/31/2019. Patients were dichotomized by whether they had ≥2 follicles >20 mm on trigger day. Group A consisted of patients with <2 follicles >20 mm on trigger day and Group B consisted of patients with ≥2 follicles >20 mm on trigger day. The primary outcome was the number of mature oocytes retrieved. Secondary outcomes included pregnancy and live birth rates.

RESULTS

A total of 635 patients were included: (Group A = 399 patients and Group B = 236 patients). The median (IQR) diameter of the largest follicle was 20.0 mm (19.0-21.0) in Group A and 22.7 mm (21.8-24.0) in Group B (p < 0.001). Among the entire cohort, mean number of oocytes retrieved was significantly higher in Group B (9.9 ± 6.5; RR 1.08 (95% CI 1.03-1.14)) compared to Group A (9.2 ± 6.3). In a subgroup analysis of patients in the upper quartile for age (≥41.7 years), Group B had significantly more oocytes retrieved (8.1 ± 5.9 vs. 6.7 ± 4.5; RR 1.23 (95% CI 1.10-1.38)), more mature oocytes retrieved (6.0 ± 4.0 vs. 5.2 ± 3.4; RR 1.16 (95% CI 1.02-1.33)), and more zygotes (4.7 ± 3.5 vs. 3.6 ± 2.8; RR 1.32 (95% CI 1.13-1.55)). In the secondary analysis, pregnancy and live birth rates after fresh transfer were similar between groups.

CONCLUSIONS

In clomiphene citrate-based IVF protocols, administering the ovulatory trigger at larger follicle sizes yielded more total oocytes retrieved without a significant difference in mature oocyte number. In older patients, larger follicle sizes at trigger yielded more mature oocytes and zygotes per retrieval. Based on these results, in older patients it may be advantageous to administer the ovulatory trigger in clomiphene-based IVF cycles when two or more follicles measures >20 mm. However, this benefit was not observed when assessed among all ages combined.

Three-Dimensional Automated Volume Calculation (Sonography-Based Automated Volume Count) versus Two-Dimensional Manual Ultrasonography for Follicular Tracking and Oocyte Retrieval in Women Undergoing in vitro Fertilization-Embryo Transfer: A Randomized Controlled Trial

Aim:

To compare the oocyte yield using three-dimensional (3D) automated and two-dimensional (2D) ultrasound-based follicle tracking in women undergoing in vitro fertilization-embryo transfer (IVF-ET).

Settings and Design:

A randomized controlled trial was conducted in the Reproductive Medicine Unit of a teaching medical institute from January 2017 to December 2018.

Materials and Methods:

A total of 130 patients undergoing IVF-ET were enrolled and randomized into two groups (65 patients in each group). In Group A, follicular tracking during controlled ovarian stimulation (COS) was done using 3D Sonography- based Automated Volume Count (SonoAVC), whereas in Group B, follicular tracking was done by manual ultrasonography (2D USG). The primary outcome measures were the number of oocytes retrieved (the total number and the number of mature oocytes). Secondary outcomes were fertilization rate, cleavage rate, total number of embryos and time taken to perform scans. Other outcome measures were clinical pregnancy rate, miscarriage rate and live birth rate (LBR).

Statistical Analysis Used:

Chi-square test, Student's t-test, Z-test, Wilcoxon rank-sum test, Bland–Altman's plot.

Results:

The two groups were comparable with regard to assisted reproductive technology (ART) outcomes. Group B required more time for performing the scan (P < 0.01).

Conclusion:

Automated SonoAVC ultrasound can be used interchangeably with manual 2D USG for follicle tracking during COS giving comparable ART outcomes with the added advantage of saving time. Our study implies the promising results of applying artificial intelligence in follicular tracking during COS.

Does a Large (>24 mm) Follicle Yield a Competent Oocyte/Embryo?

AIM

To evaluate the effect of large follicular size (≥24 mm) at day of oocyte retrieval on oocyte/embryo quality.

PATIENTS AND METHODS

A cohort study was conducted in a single tertiary medical center between July 2018 and May 2019. Before ultrasound-guided follicular aspiration, follicles were measured and divided into 2 groups according to their maximal dimensional size: large: ≥24 mm and normal: <24 mm. Microscopic examination of the follicular aspirates was performed by an embryologist. Each follicle aspirated was evaluated for oocyte maturation, oocyte fertilization, and embryo quality.

RESULTS

428 follicles were measured, including 383 (62.81%) in the normal and 45 (14.06%) in the large follicle groups. Oocytes were achieved during aspiration from 297 (75.5%) and 29 (64.4%) of the normal and large follicle groups, respectively (p = 0.05). No in-between group differences were observed in mature oocyte (MII), fertilization, and top-quality embryo (TQE) rates. Nevertheless, once a zygote (2PN) was achieved, a trend toward a higher TQE rate/2PN was found in the large follicle group (16/19 [84.2%] vs. 115/171 [67.3%]; p = 0.062).

CONCLUSION

While a nonsignificant decrease in oocyte recovery rate was found in follicles ≥24 mm, the zygote and TQE per follicle were comparable.

Do Follicles of Obese Patients Yield Competent Oocytes/Embryos?

AIM

This study evaluated the competency of oocytes/embryos derived from follicles >15 mm in diameter from obese patients, compared with nonobese patients.

PATIENTS AND METHODS

A cohort study was conducted in a single tertiary medical center between July 2018 and May 2019. Before ultrasound-guided follicular aspiration, follicles were measured and those with maximal dimensional size >15 mm were tracked. Microscopic examination of the follicular aspirates was performed by an embryologist. Each follicle aspirated was evaluated for oocyte maturation, oocyte fertilization, and embryo quality.

RESULTS

457 follicles were measured: 380 (83.2%) in nonobese and 77 (16.8%) in obese patients. No in-between group differences were observed in the causes of infertility, patients' demographics, or ovarian stimulation characteristics. Oocytes were achieved during aspiration from 277 (72.8%) and 54 (70.0%) of the nonobese and obese groups, respectively (p = 0.67). No in-between group differences were observed in fertilization (2PN/oocyte), top quality embryo (TQE) per zygote (2PN), and TQE per follicle.

CONCLUSION

Oocyte recovery rate from follicles >15 mm is unrelated to patients' BMI. Moreover, the oocytes recovered from obese patients are competent yielding comparable zygote and TQE per follicle/oocyte, compared with nonobese patients. Further investigation is required to strengthen this finding.

The role of color Doppler in assisted reproduction: A narrative review

Color Doppler of perifollicular vascularity is a useful assessment tool to predict the growth potential and maturity of Graafian follicles. Power Angio is independent of the angle of insonation and morphometry and provides reliable clues to predict the implantation window of the endometrium. Color Doppler can be used for the prediction of ovarian hyperstimulation syndrome. It can also be used to identify the hyper responder and gonadotropin-resistant type of polycystic ovaries. The secretory scan of corpus luteum can accurately predict its vascularity and functional status. A corpus luteum with decreased blood flow is a very sensitive and specific indicator of threatened and missed abortions. Color Doppler and Power Angio need to be standardized and identical settings should be maintained if different patients, or if changes over time within the same patient are to be compared.

Inhibin A-A Promising Predictive Parameter for Determination of Final Oocyte Maturation in Ovarian Stimulation for IVF/ICSI

The number of mature oocytes is a key factor in the success of Assisted Reproductive Techniques (ART). Exogenous gonadotropins are administered during ovarian stimulation in order to maximize the number of oocytes available for fertilization. During stimulation, monitoring is mandatory to evaluate individual response, to avoid treatment complications and assist in the determination of the optimal day for final oocyte maturation and oocyte retrieval. Routine monitoring during stimulation includes transvaginal ultrasound examinations and measurement of serum estradiol (E2). Due to multifollicular growth of follicles of varying size, serum E2 levels are commonly supraphysiological and often variable, rendering E2-measurement during ovarian stimulation unreliable as a determinant of oocyte maturity. In contrast to serum E2, serum Inhibin A levels increase once a minimum follicle size of 12-15 mm is achieved. Due to this fact, serum Inhibin A levels could present in combination with ultrasound monitoring a more reliable parameter to determine the optimal follicle size for final oocyte maturation, as only follicles with a size of 12 mm and beyond will contribute to the serum Inhibin A level. This prospective observational, cross-sectional study demonstrates, that on the day of final oocyte maturation serum Inhibin A is strongly correlated to the number of follicles ≥15 mm (0.72) and to the number of retrieved and mature oocytes (ρ 0.82/0.77, respectively), whereas serum E2 is moderately correlated to the parameters mentioned above (ρ 0.64/0.69/0.69, respectively). With an area under the curve (AUC) of 0.91 for Inhibin A, compared to an AUC of 0.84 for E2, Inhibin A can be regarded as a better predictor for the optimal timing of trigger medication with a threshold number of ≥10 mature oocytes. It can be concluded from this data that serum Inhibin A in combination with transvaginal ultrasound monitoring may be a more powerful tool in the decision making process on trigger timing as compared to E2.

An objective volumetric method for assessment of ovarian follicular and luteal vascular flow using colour Doppler ultrasonography

Our goal was to develop an objective computer-assisted volumetric method of assessing vascular flow from colour Doppler ultrasound data of ovarian structures recorded by free-hand movement. We hypothesized that a vascularity index (ratio of the region of blood flood to the region of ovarian structure) obtained from the three-dimensional volumetric analysis would be more precise (less variable) than conventional two-dimensional analysis of single images in estimating the functional status of the preovulatory follicles and corpus luteum. Doppler ultrasound cineloops of water buffaloes (Bubalus bubalis; n = 22) ovaries were recorded daily from 12 h before GnRH treatment to four days after ovulation. Cineloops were processed using Fiji and Imaris software packages for segmenting the area (two-dimensional analysis) and the volume (three-dimensional analysis) occupied by the blood-flow and associated tissue to calculate the vascularity index. For volumetric measurement, all images in a cineloop were used (i.e., no a-priori selection of images) while for two-dimensional analysis, three images from the region with apparent maximum vascularity were selected. The volumetric method was verified with theoretical ellipsoidal volume of the follicle (r = 0.96 P < 0.01) or corpus luteum (r = 0.58 P = 0.02). The variability in the follicular vascularity index among animals was lower using the volumetric method than two-dimensional analysis (0.018 ± 0.002 vs 0.030 ± 0.005, P < 0.01), while the variability for CL vascularity was similar between methods (P = 0.23). An increase in the follicular vascularity index was detected at 12 h after GnRH treatment using both methods (two-dimensional: 0.030 ± 0.008, P < 0.01; three-dimensional: 0.016 ± 0.006, P < 0.02). Buffaloes that ovulated tended to have a greater increase in 3D vascularity index than non-responding buffaloes (P = 0.06); the two-dimensional method was not able to detect these changes. Using the three-dimensional method, a moderate positive correlation (r = 0.59; P = 0.02) was evident between the follicular vascularity index at 14-16 h after GnRH treatment and follicular diameter. In conclusion, an objective volumetric method for assessing relative ovarian blood flow changes was developed using Doppler ultrasound cineloops recorded by free-hand movement. The 3-dimensional method eliminates the need for a-priori selection of images and is more precise as a result of decreased technical variability.

A Higher Estradiol Rise After Dual Trigger in Progestin-Primed Ovarian Stimulation Is Associated With a Lower Oocyte and Mature Oocyte Yield in Normal Responders

Background: Prior studies have shown that patients with a >10% estradiol (E₂) rise after trigger had more oocytes retrieved than plateauing or decreasing E₂ responders. However, multiple follicles develop at different stages of maturation during controlled ovarian stimulation (COS) and may exhibit different responses to trigger. The association between the magnitude of E₂ increase and oocyte retrieval outcomes is still unclear. Methods: This was a retrospective cohort study of 2,898 women undergoing their first COS cycles with normal response from January 2014 to December 2017 at a tertiary-care academic medical center. Patients were categorized into five groups according to the percentage increase in E₂ levels before and after dual trigger: <10.0%, 10.0-19.9%, 20.0-29.9%, 30.0-39.9%, and ≥40.0%. Univariable and multivariable linear regression analysis were performed to explore the association between E₂ increase and oocyte/mature oocyte yield, while logistic regression was used to assess its effect on low oocyte/mature oocyte yield (<10th percentile). Results: The post-trigger E₂ increase was negatively associated with both oocyte yield (P-trend < 0.001, adjusted P-trend = 0.033) and mature oocyte yield (P-trend < 0.001, adjusted P-trend = 0.002). Compared with a <10.0% E₂ increase after trigger, patients with a ≥40.0% rise had fewer mature oocyte yield [adjusted mean absolute difference [MD] = -5.2, 95% confidence interval [CI]: -8.2--1.8] and higher risk of low mature oocyte yield (adjusted odds ratio [OR] = 1.64, 95% CI: 1.04-2.60), whereas no statistical significance was found in oocyte yield (adjusted MD = -2.7, 95% CI: -6.1-0.8) and low oocyte yield (adjusted OR = 1.48, 95% CI: 0.96-2.28). In addition, the rates of implantation, positive pregnancy test, clinical pregnancy, ongoing pregnancy, pregnancy loss, and live birth were comparable among the 1,942 frozen embryo transfer cycles with embryos originating from different groups of E₂ increase (all P > 0.05). Conclusions: A higher E₂ rise after dual trigger is independently associated with a lower oocyte and mature oocyte yield in normal responders. Further studies are needed to explore the efficacy of individualized time interval from trigger to oocyte retrieval based on the magnitude of E₂ increase after trigger.

Novel Concepts for Inducing Final Oocyte Maturation in In Vitro Fertilization Treatment

Infertility affects one in six of the population and increasingly couples require treatment with assisted reproductive techniques. In vitro fertilization (IVF) treatment is most commonly conducted using exogenous FSH to induce follicular growth and human chorionic gonadotropin (hCG) to induce final oocyte maturation. However, hCG may cause the potentially life-threatening iatrogenic complication "ovarian hyperstimulation syndrome" (OHSS), which can cause considerable morbidity and, rarely, even mortality in otherwise healthy women. The use of GnRH agonists (GnRHas) has been pioneered during the last two decades to provide a safer option to induce final oocyte maturation. More recently, the neuropeptide kisspeptin, a hypothalamic regulator of GnRH release, has been investigated as a novel inductor of oocyte maturation. The hormonal stimulus used to induce oocyte maturation has a major impact on the success (retrieval of oocytes and chance of implantation) and safety (risk of OHSS) of IVF treatment. This review aims to appraise experimental and clinical data of hormonal approaches used to induce final oocyte maturation by hCG, GnRHa, both GnRHa and hCG administered in combination, recombinant LH, or kisspeptin. We also examine evidence for the timing of administration of the inductor of final oocyte maturation in relationship to parameters of follicular growth and the subsequent interval to oocyte retrieval. In summary, we review data on the efficacy and safety of the major hormonal approaches used to induce final oocyte maturation in clinical practice, as well as some novel approaches that may offer fresh alternatives in future.

Follicle Size on Day of Trigger Most Likely to Yield a Mature Oocyte

OBJECTIVE

To identify follicle sizes on the day of trigger most likely to yield a mature oocyte following hCG, GnRH agonist (GnRHa), or kisspeptin during IVF treatment.

DESIGN

Retrospective analysis to determine the size of follicles on day of trigger contributing most to the number of mature oocytes retrieved using generalized linear regression and random forest models applied to data from IVF cycles (2014-2017) in which either hCG, GnRHa, or kisspeptin trigger was used.

SETTING

HCG and GnRHa data were collected at My Duc Hospital, Ho Chi Minh City, Vietnam, and kisspeptin data were collected at Hammersmith Hospital, London, UK.

PATIENTS

Four hundred and forty nine women aged 18-38 years with antral follicle counts 4-87 were triggered with hCG (n = 161), GnRHa (n = 165), or kisspeptin (n = 173).

MAIN OUTCOME MEASURE

Follicle sizes on the day of trigger most likely to yield a mature oocyte.

RESULTS

Follicles 12-19 mm on the day of trigger contributed the most to the number of oocytes and mature oocytes retrieved. Comparing the tertile of patients with the highest proportion of follicles on the day of trigger 12-19 mm, with the tertile of patients with the lowest proportion within this size range, revealed increases of 4.7 mature oocytes for hCG (P < 0.0001) and 4.9 mature oocytes for GnRHa triggering (P < 0.01). Using simulated follicle size profiles of patients with 20 follicles on the day of trigger, our model predicts that the number of oocytes retrieved would increase from a mean 9.8 (95% prediction limit 9.3-10.3) to 14.8 (95% prediction limit 13.3-16.3) oocytes due to the difference in follicle size profile alone.

CONCLUSION

Follicles 12-19 mm on the morning of trigger administration were most likely to yield a mature oocyte following hCG, GnRHa, or kisspeptin.

Relationship between follicular volume and oocyte competence, blastocyst development and live-birth rate: optimal follicle size for oocyte retrieval

OBJECTIVE

To analyze oocyte competence in gonadotropin-releasing hormone agonist (GnRHa) stimulation cycles with regard to maturity, fertilization and blastocyst rate, as well as clinical outcome (pregnancy and live-birth rate), in relation to follicular volume, measured by three-dimensional transvaginal sonography (3D-TVS), and follicular fluid composition.

METHODS

This was a prospective single-center study conducted between June 2012 and June 2014, including 118 ovum pick-ups with subsequent embryo transfer. Ovarian stimulation was performed using the GnRHa long protocol. Of 1493 follicles aspirated individually, follicular volume was evaluated successfully in 1236 using automated 3D-TVS during oocyte retrieval. Oocyte maturity and blastocyst development were tracked according to follicular volume. Intrafollicular concentrations of estradiol, testosterone, progesterone, luteinizing hormone, follicle-stimulating hormone and granulocyte-colony stimulating factor were quantified by immunoassay. Clinical outcome, in terms of implantation rate, (clinical) pregnancy rate, miscarriage and live-birth rate (LBR), was evaluated.

RESULTS

Follicles were categorized, according to their volume, into three arbitrary groups, which included 196 small (8-12 mm/0.3-0.9 mL), 772 medium (13-23 mm/1-6 mL) and 268 large (≥ 24 mm/> 6 mL) follicles. Although oocyte recovery rate was significantly lower in small follicles compared with medium and large ones (63.8% vs 76.6% and 81.3%, respectively; P < 0.001), similar fertilization rates (85.1% vs 75.3% and 81.4%, respectively) and blastocyst rates (40.5% vs 40.6% and 37.2%, respectively) per mature metaphase II oocyte were observed. A trend towards higher LBR after transfer of blastocysts derived from small (< 1 mL) follicles compared with medium (1-6 mL) or large (> 6 mL) follicles (54.5% vs 42.0%, and 41.7%, respectively) was observed. No predictive value of follicular fluid biomarkers was identified.

CONCLUSIONS

Our data indicate that the optimal follicular volume for a high yield of good quality blastocysts with good potential to lead to a live birth is 13-23 mm/1-6 mL. However, oocytes derived from small follicles (8-12 mm/0.3-0.9 mL) still have the capacity for normal development and subsequent delivery of healthy children, suggesting that aspiration of these follicles should be encouraged as this would increase the total number of blastocysts retrieved per stimulation. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Empty follicle syndrome revisited: definition, incidence, aetiology, early diagnosis and treatment

In this review, the definition, incidence and possible causes of empty follicle syndrome (EFS), including molecular mechanisms that may underlie the syndrome, are discussed, along with prevention and treatment options. EFS is the complete failure to retrieve oocytes after ovarian stimulation, despite apparently normal follicle development and adequate follicular steroidogenesis. Two variants of EFS have been described: the 'genuine' form (gEFS), which occurs in the presence of adequate circulating HCG levels at the time of oocyte aspiration, and the 'false' form (f-EFS), which is associated with circulating HCG below a critical threshold. Heterogeneous HCG concentration thresholds, however, have been used to define gEFS, and to date no standardization exist. The situation is unclear when GnRH-analogues are used for ovulation trigger, as the threshold circulating LH and progesterone levels used to define EFS as 'genuine' are not established. The cause of fEFS has been clearly identified as an error in HCG administration at the time of ovulation trigger; in contrast, the cause of gEFS is still unclear, although some pathogenetic hypotheses have been proposed. Optimal treatment and prognosis of these patients are still poorly understood. Large, systematic multi-centre studies are needed to increase the understanding of EFS.