Optimal lead follicle size for human chorionic gonadotropin trigger in clomiphene citrate and intrauterine insemination cycles: an analysis of 1,676 treatment cycles

Extended versus conventional letrozole regimen in patients with polycystic ovary syndrome undergoing their first ovulation induction cycle: a prospective randomized controlled trial

STUDY QUESTION

Can an extended letrozole (LE) regimen result in a higher ovulatory rate than a conventional regimen in patients with polycystic ovary syndrome (PCOS) undergoing their first ovulation induction cycle?

SUMMARY ANSWER

There was no statistical difference in ovulation rate between patients with PCOS using the extended LE regimen and those using the conventional LE regimen.

WHAT IS KNOWN ALREADY

LE has become the first-line agent for ovulation induction. However, there is still a proportion of non-responsive cycles in patients with PCOS undergoing ovulation induction therapy with LE alone, and the extended LE regimen has been demonstrated to be a feasible method for inducing ovulation in these non-responders. Nevertheless, whether the extended regimen could be applied to all patients with PCOS as a first choice for the induction of ovulation remains to be explored.

STUDY DESIGN SIZE DURATION

This was a prospective randomized controlled trial that included 148 female patients with PCOS who underwent their first ovulation induction cycle with LE from January 2021 to October 2022.

PARTICIPANTS/MATERIALS SETTING METHODS

Participants were randomly assigned to receive an extended (5 mg LE daily for 7 days) or conventional regimen (5 mg LE daily for 5 days) for one treatment cycle. The ovulation rate was the primary outcome. Secondary outcomes included the clinical pregnancy rate, the number of preovulatory follicles, and the rate of multiple pregnancies.

MAIN RESULTS AND THE ROLE OF CHANCE

The ovulation rate among patients receiving an extended LE regimen was slightly higher than the rate with a conventional LE regimen, but the difference did not reach statistical significance in either the intention-to-treat analysis (90.54% [67/74] vs 79.73% [59/74], P = 0.065; relative risk [95% CI]: 0.881 [0.768-1.009]) or the per-protocol analysis (90.54% [67/74] vs 84.29% [59/70], P = 0.257; relative risk [95% CI]: 0.931 [0.821-1.055]). The number of preovulatory follicles was nearly identical in the two groups (1.39 ± 0.62 vs 1.37 ± 0.59, P = 0.956), and no cases of ovarian hyperstimulation syndrome were observed. With regards to the endometrial parameters, the mean endometrium thickness was slightly thicker with the conventional LE regimen compared to that with the extended LE regimen, though with no statistical difference (9.27 ± 1.72 mm vs 9.57 ± 2.28 mm, P = 0.792). In the per-protocol analysis, the rates of clinical pregnancy (20.27% [15/74] vs 14.29% [10/70], P = 0.343; relative risk [95% CI]: 0.705 [0.34-1.463]) and live birth (13.51% [10/74] vs 11.43% [8/70], P = 0.705; relative risk [95% CI]: 0.846 [0.354-2.019]) did not differ significantly between treatment groups. Moreover, all conceptions were singletons without neonatal defects.

LIMITATIONS REASONS FOR CAUTION

The major concerns regarding this study are its single-center and open-label nature. Additionally, the limited number of lean patients with PCOS with a mean body mass index of 23-25 kg/m2 enrolled in our trial also restricted the generalizability of our findings.

WIDER IMPLICATION OF THE FINDINGS

A change from the standard strategy of ovulation induction in patients with PCOS is not advisable, because a statistically superior effect of the extended LE regimen over a conventional regimen was not detected. The extended LE regimen could be applied with caution in a specific population who failed to respond to a conventional regimen rather than all the patients with PCOS during ovulation induction. Additional prospective trials with larger sample sizes and different PCOS subgroups are needed to assess the ovulatory effects of various LE treatment durations.

STUDY FUNDING/COMPETING INTERESTS

This study was funded by the Shanghai First Maternity and Infant Hospital, affiliated with Tongji University School of Medicine (grant numbers: 2023B03 to Y.F., 2023B18 to X.Z., and 2020RC02 to Y.F.). The authors report no conflicts of interest.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry (ChiCTR2100042082).

TRIAL REGISTRATION DATE

13 January 2021.

DATE OF FIRST PATIENT’S ENROLMENT

21 January 2021.

Effect of the degree of follicular diameter ≥18mm differentiation on the day of hCG administration to the outcome of controlled ovarian hyperstimulation (COH)

Objective

To explore the impact of the level of differentiation in a minimum of two follicles with a diameter of ≥18 mm on the outcome of controlled ovarian hyperstimulation on the day of human chorionic gonadotropin (hCG) administration.

Methods

Single-center data from January 2018 to December 2021 was retrospectively analyzed for 1,199 patients with fresh embryo transfer for assisted reproduction. The absolute value of the standard deviation of the follicle size of at least 2 follicles ≥18 mm in diameter in both ovaries on the day of hCG was taken as the degree of differentiation of the dominant follicle after ovulation induction, based on the standard deviation response to the degree of dispersion of the data. The degree of follicular differentiation was divided into 3 groups according to the size of the value, and the general clinical conditions, laboratory indexes, and clinical outcomes of the patients in the 3 groups were compared.

Results

Among the three groups, the body mass index (BMI) of the ≤1s group was lower than that of the other two groups (P< 0.05), while the follicle-stimulating hormone (FSH) and Anti-Mullerian hormone (AMH) were higher (P< 0.05), and the implantation rate and clinical pregnancy rate were significantly higher than those of the other two groups (P< 0.01). After multifactorial logistic regression to correct for confounding factors, with the ≤1s group as the reference, the implantation rate, hCG-positive rate, clinical pregnancy rate and live birth rate of embryo transfer in the ≥2S group were significantly lower (P< 0.01). The results of curve fitting analysis showed that the live birth rate decreased gradually with the increase of the absolute standard deviation (P=0.0079).

Conclusion

Differences in follicle diameters ≥18 mm on the day of hCG injection did not have an impact on embryo quality, but had an impact on pregnancy outcomes. The less the variation in follicle size, the more homogeneous the follicle development and the higher the likelihood of live births.

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.

Association between follicle size, endometrial thickness, and types of ovarian stimulation (Clomiphene citrate and Letrozole) with biochemical pregnancy rate in women undergone intrauterine insemination

OBJECTIVE

There was also a lack of data regarding the effect of follicle size, endometrial thickness, and ovarian stimulation as predictors of intrauterine insemination (IUI) success rate in Indonesia, especially in the Aster Clinic and Bandung Fertility Centre. This study was performed to explore the relationship between follicle size, endometrial thickness, and types of ovarian stimulation (Clomiphene citrate/CC vs Letrozole) with biochemical pregnancy rate in women undergone IUI. We performed a case-control study in 122 women aged 20-40 years with unexplained infertility who had completed the IUI program for a maximum of three cycles. Data were extracted from medical records. Independent T-test and multivariate analyses were used to analyse the difference between variables using IBM SPSS 24.0. P-value < 0.05 was considered statistically significant.

RESULT

Follicle sizes of 18-22 mm in both Clomiphene citrate (CC) and Letrozole groups were shown to increase biochemical pregnancy rate (P = 0.001). There is no relationship between endometrial thickness and pregnancy rate. Biochemical pregnancy rate in women using Letrozole was 1.513 times higher than women using CC. The follicle size of 18-22 mm and using Letrozole rather than CC as ovarian stimulators are predictive factors associated with a higher pregnancy rate in women undergone IUI.

Intrauterine Insemination After Human Chorionic Gonadotropin Trigger or Luteinizing Hormone Surge: A Meta-analysis

OBJECTIVE

To assess the odds of pregnancy after intrauterine insemination (IUI) timed by ultrasound monitoring and human chorionic gonadotropin (hCG) administration compared with monitoring luteinizing hormone (LH) levels.

DATA SOURCES

We searched PubMed (MEDLINE), EMBASE (Elsevier), Scopus (Elsevier), Web of Science (Clarivate Analytics), ClinicalTrials.gov (National Institutes of Health), and the Cochrane Library (Wiley) from the inception until October 1, 2022. No language limitations were applied.

METHODS OF STUDY SELECTION

After deduplication, 3,607 unique citations were subjected to blinded independent review by three investigators. Thirteen studies (five retrospective cohort, four cross-sectional, two randomized controlled trials, and two randomized crossover studies) that enrolled women undergoing natural cycle, oral medication (clomid or letrozole), or both for IUI were included in the final random-effects model meta-analysis. Methodologic quality of included studies was assessed with the Downs and Black checklist.

TABULATION, INTEGRATION, AND RESULTS

Data extraction was compiled by two authors, including publication information, hCG and LH monitoring guidelines, and pregnancy outcomes. No significant difference in odds of pregnancy between hCG administration and endogenous LH monitoring was observed (odds ratio [OR] 0.92, 95% CI 0.69-1.22, P=.53). Subgroup analysis of the five studies that included natural cycle IUI outcomes also showed no significant difference in odds of pregnancy between the two methods (OR 0.88, 95% CI 0.46-1.69, P=.61). Finally, a subgroup analysis of 10 studies that included women who underwent ovarian stimulation with oral medications (clomid or letrozole) did not demonstrate a difference in odds of pregnancy between ultrasonography with hCG trigger and LH-timed IUI (OR 0.88, 95% CI 0.66-1.16, P=.32). Statistically significant heterogeneity was noted between studies.

CONCLUSION

This meta-analysis showed no difference between pregnancy outcomes between at-home LH monitoring and timed IUI.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42021230520.

Optimal lead follicle size in letrozole human menopausal gonadotrophin intrauterine insemination cycles with and without spontaneous LH surge

RESEARCH QUESTION

What is the optimal lead follicle size in letrozole, human menopausal gonadotrophin and intrauterine insemination (IUI) cycles with and without spontaneous LH surges?

DESIGN

This retrospective cohort study included 3797 letrozole HMG IUI cycles between January 2010 and May 2021. All cycles were divided into two groups: the HCG trigger group (trigger day LH ≤15 mIU/ml) and the spontaneous LH surge group (trigger day LH >15 mIU/ml). These two groups were subdivided into smaller groups based on the diameter of the follicles. The primary outcome measure was clinical pregnancy rate. Logistic regression analysis was conducted to explore other risk factors.

RESULTS

In the HCG trigger group, the clinical pregnancy rate varied significantly, with rates of 20.8%, 14.9% and 11.8% for the 16.1-18.0, 18.1-20.0 and 20.1-22.0 mm groups, respectively (P = 0.005). In the spontaneous LH surge group, the pregnancy rate of follicles within 14.1-16.0 mm was significantly higher than that of follicles within 20.1-22.0 mm (adjusted OR 0.533, 95% CI 0.308 to 0.923, P = 0.025). Also, patients with two lead follicles were 2.569 times more likely to achieve a clinical pregnancy than those with only one lead follicle (adjusted OR 2.569, 95% CI 1.258 to 5.246, P = 0.010). The duration of infertility was also found to be a common influencing factor in both groups.

CONCLUSIONS

The optimal lead follicle size was between 16.1 and 18.0 mm in HCG-triggered letrozole HMG IUI cycles. If the lead follicle size is relatively small (14.1-18.0 mm) when a spontaneous LH surge occurs, there is no need to cancel the IUI cycle.

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.