Comparison of estradiol and progesterone priming/antagonist/letrozole and microdose flare-up protocols for poor responders undergoing intracytoplasmic sperm injection

Impact of 2.5 mg versus 5 mg letrozole co-treatment in an antagonist protocol for IVF: a retrospective study

Objective

The present study aimed to compare the effectiveness of two different doses of letrozole (2.5 mg and 5 mg daily) in an antagonist protocol for infertile women with normal ovarian reserve.

Methods

This retrospective cohort study included infertile women who underwent in vitro fertilization treatment with letrozole co-treatment at doses of 2.5 mg and 5 mg from 2007 - 2021 at Shanghai Ninth People's Hospital (Shanghai, China). The control group comprised infertile women who received gonadotropin-releasing hormone antagonist alone. The primary outcome was the cumulative live birth rate, while secondary outcomes included follicular phase endocrine parameters, ovarian stimulation outcomes, pregnancy outcomes, and the incidences of maternal and neonatal complications. Baseline and follow-up data were compared between the groups using ANOVA for normally distributed variables, the Kruskal-Wallis test for non-normally distributed variables, and the Chi-square test for categorical variables.

Results

A total of 422 participants were enrolled in the study, with 211 women in the antagonist group, 109 women in the 2.5 mg letrozole co-treatment group, and 102 women in the 5 mg letrozole co-treatment group. Letrozole co-treatment significantly suppressed oestradiol and follicle-stimulating hormone concentrations from stimulation day 5 and onwards, while increasing luteinizing hormone levels on stimulation day 5 and trigger day. The effect was more pronounced with a 5 mg dose of letrozole compared to a 2.5 mg dose (P < 0.05). Administration of 5 mg letrozole reduced the gonadotropin dose (P < 0.05) without negatively affecting the number of oocytes retrieved and subsequent embryo parameters (P > 0.05). The analysis of cumulative live birth rates showed rates of 29.4% in the letrozole 5 mg group, 27.5% in the letrozole 2.5 mg group, and 33.6% in the control group, with no statistically significant difference (P > 0.05). There were no reported pregnancy complications in the two letrozole groups. Additionally, there were no significant differences among the three groups in terms of gestational age and birth weight for both singleton and twin births.

Conclusion

This study indicates that the administration of letrozole in an antagonist protocol, at both 2.5 mg and 5 mg dosages, results in comparable clinical outcomes.

Risk of foetal harm with letrozole use in fertility treatment: a systematic review and meta-analysis

BACKGROUND

The aromatase inhibitor letrozole is increasingly recommended for ovulation induction, as it is more effective with fewer side-effects than other agents. But many clinicians are reluctant to use the drug for fertility treatment due to a strong-label warning against its use, which warns about congenital malformation risk to the foetus in women seeking pregnancy.

OBJECTIVE AND RATIONALE

The aim of this study was to determine the risks of congenital malformations and pregnancy loss with letrozole compared with clomiphene primarily, and with other fertility drugs and natural conception.

SEARCH METHODS

A systematic review and meta-analysis using PRISMA harms guidelines. We searched MEDLINE, EMBASE and other sources from inception until January 2020, with the MeSH words for 'letrozole' and pregnancy OR foetal/neonatal outcome. We included studies reported on congenital malformations in foetuses born to mothers conceived after fertility treatment, with letrozole versus clomiphene, placebo, gonadotrophins, metformin, natural conception or other agents, from randomised trials, comparative cohort studies and non-comparative observational cohorts. Quality of the studies was assessed using Cochrane risk of bias tool and Newcastle Ottawa Scale. The McMaster tool was used to assess the quality of reported harm for foetal congenital malformations in the studies. We compared the absolute risk of events using risk difference measures and pooled the findings using a fixed-effect model. We evaluated the statistical heterogeneity using forest plots and the I2 statistic and funnel plot to assess publication bias. We assessed the strength of evidence for congenital malformation and pregnancy loss as per the GRADE recommendations and with the Fragility index.

OUTCOMES

We included 46 studies (18 randomised trials; 21 comparative cohorts; 7 non-comparative cohorts). Overall 2.15% (101/4697; 95% CI 1.7 to 2.5) of babies conceived on letrozole for fertility treatment had congenital foetal malformations. We did not observe a significant increase in congenital malformations with letrozole versus clomiphene in the randomised trials (risk difference (RD) 0.01, 95% CI -0.02, 0.03; I2 = 0%; 14 studies) and found a significant reduction in the cohort studies (RD -0.02, 95% CI -0.04, -0.01; I2 = 0%, 11 studies). The fragility index was 44% (7/16) (either an increase in the intervention arm or a decrease in control arm was needed to alter the results). The risks of pregnancy loss were not increased with letrozole versus clomiphene in the 14 randomised trials (RD -0.01, 95% CI -0.06, 0.04; I2 = 0%), and the risks were reduced in the six cohort studies (RD -0.09, 95% CI -0.17, -0.00; I2 = 68%). The GRADE quality of evidence was low to moderate for congenital malformations and pregnancy loss. We did not find any increased congenital malformation risk with letrozole versus gonadotrophins, natural conception or natural cycle ART, but the number of studies was small.

WIDER IMPLICATIONS

There is no evidence that letrozole increases the risk of congenital foetal malformation or pregnancy loss compared with clomiphene, natural conception or other fertility agents, to warrant warning against its use. Given its therapeutic benefits and lack of evidence of harm to the foetus, clinicians should consider letrozole as first-line agent for ovulation induction.

Cumulative live birth rate of advanced-age women more than 40 with or without poor ovarian response

OBJECTIVE

The aim of this study was to investigate cumulative live birth rate (CLBR) per oocyte retrieval cycle and per patient in women over 40 years old undergoing IVF/ICSI treatments, stratified for age, ovarian response and oocyte retrieval cycle number.

MATERIALS AND METHODS

244 patients with poor ovarian response (POR) and 372 patients with normal ovarian response (NOR) were retrospectively investigated.

RESULTS

Of the patients aged 40 to 43 years, CLBR per oocyte retrieval cycle and per patient (4.3%; 8.8%) in POR group were both lower than those in NOR group (15.8%; 24.8%) (P < 0.01). No significant differences in live birth rate (LBR) per oocyte retrieval cycle or CLBR per patient were observed in the group of POR patients irrespective of oocyte retrieval cycles they underwent. Similarly, CLBR per patient in NOR group did not increase significantly with the oocyte retrieval cycle number. However, LBR per oocyte retrieval cycle in the first cycle (Cycle 1, 20.3%) was significantly higher than that in the second cycle (Cycle 2, 9.2%) and the third cycle (Cycle 3, 4.4%) (P < 0.01). And 94.8% (73/77) of live births were achieved during the first two cycles. Of the patients aged 44 to 45 years and over 45 years old, there were no significant differences in CLBR per oocyte retrieval cycle or per patient between POR and NOR groups.

CONCLUSION

Relatively higher cumulative live birth rate was only found in the patients aged 40 to 43 years without poor ovarian response. These findings may provide some information that further sub-classification of advance-age women according to ovarian response may help both clinicians and patients to balance decision-making about their infertility treatment.

A comparison of treatment results of the different treatment protocols in patients with poor ovarian response

To compare the effect of the different protocols in patients receiving in vitro fertilization treatment due to poor ovarian response. Seventy-seven of the patients included in the study were treated with gonadotropin (450 IU) + GnRH antagonist (group 1), 84 of the patients were treated with gonadotropin (450 IU) + microdose GnRH analog (group 2), and 53 of the patients were treated with clomiphene citrate (100 mg/day) + gonadotropin (300 IU) + GnRH antagonist (Group 3). In assessing total gonadotropin dosage, patients in Group 3 detected significantly less gonadotropin as compared to the other two groups (p < .001). Group 1 were superior to the other two groups with respect to retrieved oocytes, meiosis II oocytes and number of embryos obtained at the end of the treatment. As for the evaluation of clinical pregnancy, although the highest pregnancy rate was in Group 3, this finding was not of statistical significance. Although increasing the dosage of gonadotropins for ovarian hyper stimulation treatment in patients with poor ovarian response is beneficial with respect to retrieved oocytes, meiosis II oocytes and number of embryos, the increased dosage does not provide a statistically significant increase in clinical pregnancy rates.

Presence of embryonic DNA in culture medium

Preimplantation genetic diagnosis (PGD) has successfully assisted couples with genetic diseases to conceive healthy babies during the past decades. However, biopsy of the blastomere has potential lesion to the embryos which commonly results in abortion. Thus, a noninvasive PGD is needed. In the past, the presence of genetic materials in maternal plasma or serum has triggered a great innovation of noninvasive prenatal diagnosis. Nevertheless, it is not clear whether embryonic DNA is also present in embryonic culture medium. Here, a rapid-boiling method has been used to harvest DNA from the medium or the discarded embryos, following Polymerase Chain Reaction (PCR) was applied to detect the dissociative DNA by amplifying SRY gene (Y-chromosome). For the first time, the Y sequences were detected in the medium which were used to culture embryo for above 3 days. None of the positive signal was examined in Day 1 and Day 2 embryonic culture medium. Our findings suggest that the Y chromosome fragments from the embryo may release into its culture medium. If validated in a larger cohort, detection of SRY gene may prove to be a useful method to screen Y-linked genetic disease. More importantly, detecting the free DNA in the embryonic culture medium may represent a novel strategy for noninvasive PGD.

Medium-based noninvasive preimplantation genetic diagnosis for human α-thalassemias-SEA

To develop a noninvasive medium-based preimplantation genetic diagnosis (PGD) test for α-thalassemias-SEA. The embryos of α-thalassemia-SEA carriers undergoing in vitro fertilization (IVF) were cultured. Single cells were biopsied from blastomeres and subjected to fluorescent gap polymerase chain reaction (PCR) analysis; the spent culture media that contained embryo genomic DNA and corresponding blastocysts as verification were subjected to quantitative-PCR (Q-PCR) detection of α-thalassemia-SEA. The diagnosis efficiency and allele dropout (ADO) ratio were calculated, and the cell-free DNA concentration was quantitatively assessed in the culture medium. The diagnosis efficiency of medium-based α-thalassemias-SEA detection significantly increased compared with that of biopsy-based fluorescent gap PCR analysis (88.6% vs 82.1%, P < 0.05). There is no significant difference regarding ADO ratio between them. The optimal time for medium-based α-thalassemias-SEA detection is Day 5 (D5) following IVF. Medium-based α-thalassemias-SEA detection could represent a novel, quick, and noninvasive approach for carriers to undergo IVF and PGD.