The main outcomes of this study
With the continuous development of ARTs, blastocyst culture has become more widely used. Meta-analysis has shown that when an equal number of embryos are transferred in a fresh IVF cycle, the probability of both live birth and clinical pregnancy is significantly higher if the embryo transfer is performed at the blastocyst stage rather than at the cleavage stage. This has been found to apply particularly to live birth rates . Another unselected patient cohort study also concluded that the cumulative live birth rate per oocyte collection cycle is higher for blastocyst-stage transfers, as compared to cleavage-stage transfers . It was found that IVF outcomes might be improved by performing blastocyst-stage transfers as compared to cleavage-stage transfers. The embryo selection and implantation processes improve with blastocyst stage transfers, while there is a demonstrable decline in multiple gestations [12–16]. Several explanations have been proposed for the superiority of blastocyst-stage transfers in improving implantation rates , and the transfer of blastocysts has become the first choice of an increasing number of patients and reproductive medical centers.
In this study, the blastocysts obtained rate for the supplementation group was 75.98%, which was significantly higher than 57.28%, for the non-supplementation group (OR=2.36, P< 0.001).
Given that live birth is the ultimate aim of ARTs, and the defining goal of each patient, the live birth rate was used as one of the main outcomes in this study. The live birth rate of the supplementation group was significantly higher than that of the non-supplementation group (P < 0.05). This indicates that DE-T1 could improve not only the outcome for blastocyst culturing, but also the outcome of the pregnancy itself.
The influences of DE-T1 on patients of differing ages and AMH levels
Studies have shown that the non-separation of meiosis chromosomes increases with age. This, in turn, leads to an increase in aneuploidy and spontaneous abortion rates in early embryos [17–18]. The most common resulting abnormality has been found to be autosomal trisomy, which is caused by an abnormal arrangement of the chromosomes and the composition of the spindle matrix during meiosis in elderly female oocytes . A 2013 study concluded that both the aneuploid rate and the no-euploid embryo rate rose in a mathematically predictable way with age .
In this study, we enrolled patients from 30 to 46 years of age. Considering the influence of age and AMH on blastocyst formation in IVF treatment, we further observed the influence of DE-T1 on patients of different age groups (≥30 to <35 years ;≥35 to <40 years༛≥40 to <43 years of age and ≥43 years of age), and different AMH levels (AMH ≤ 1.1ng/ml and AMH > 1.1ng/ml). Our results showed that the blastocyst obtained rates of the supplementation group with differing ages and AMH levels were all significantly higher than those of the non-supplementation group (P < 0.05). These results suggest that women of differing ages and AMH values could all benefit from DE-T1 supplementation during IVF treatment.
The mechanisms of DE-T1 on reproduction health
Follicular dysplasia has long been considered as one of the main causes of infertility. The causes of follicular dysplasia infertility are various. Congenital ovarian dysplasia, premature ovarian failure or ovarian lesions, excessive obesity or wasting, irregular menstruation and heredity, are the common risk factors . A variety of drugs have solved the problem of ovulation disorder in recent years, but this kind of treatment has anti-hormonal influences and can lead to the depletion of estrogen levels . The aforesaid anti-hormonal effects could inhibit endometrial DNA synthesis and cause a decrease in endometrial receptivity, while the depletion of estrogen levels could lead to increased cervical viscosity, which is not conducive to sperm passage. Therefore, any long-term use of ovulation promoting drugs tends to lower pregnancy rates and increase early abortion rates [21–22].
The Follicle-Stimulating Hormone (FSH) receptor is the only receptor present in granular cells. Our previous studies have confirmed that DE-T1 could increase the activity of FSH receptors on the surface of ovarian granulosa cells . In this study, DE-T1 supplementation significantly increased the blastocyst obtained rate in women undergoing IVF treatment. We speculate that the mechanism might be related to an increase in the number of follicular granulosa cells and a delay in the death of granulosa cells, as well as a reduction in sinusoidal cell atresia, thus increasing the quantity of mature ovum cells.
Growth hormone (GH) is also involved in many processes of human reproduction . In the process of oocyte development, GH could promote the maturity of oocytes and improve the receptor activity of granulosa cells. Further research has  found that the effect of GH on reproduction is mainly caused by promoting the secretion of insulin-like growth factor (IGF), which effectively enhances the activity of granulosa cells. It has been reported that dandelion polysaccharide could increase the activity of IGF related receptors . This may also be a contributing factor in the beneficial impact of DE-T1 on reproductive health.
To analyze the process by which DE-T1 improves live birth rates: firstly, DE-T1 significantly increased the blastocyst obtained rate of the patients in the supplementation group. Thus, the patients had more blastocysts available for ET, and therefore more chance of delivering an infant. Secondly, our previous studies have confirmed that DE-T1 can regulate the activity of multiple receptors in the ovaries and uterus, and balance the secretion of female reproductive hormones, which play a key role in ovum growth, embryo implantation, and fetal development [7–8]. In this way DE-T1 improves the quality of ova during IVF treatment and promotes high-quality fertilized embryos. We hypothesize that the improvement of live birth rates by DE-T1 supplementation was achieved through these two functions: increasing the number of blastocysts obtained and improving the quality of those blastocysts.
Research design and future prospects
With the increasing application of evidence-based methods in the field of medical research, randomized controlled trials (RCTs) and cohort studies have been widely used in clinical research. Intervention cohort studies are the main source of evidence for causal association, especially when randomized controlled trials are difficult to carry out due to ethical limitations [25–26]. Considering patients' subjective desires regarding their treatment and patient compliance, in addition to the need for long-term follow-ups and complicated interventions, we employed the methods of a retrospective cohort study to observe the influence of DE-T1 on the blastocyst obtained rates and live birth rates of women receiving IVF treatment.
We did not take the quantity of oocytes as an observation indicator for this study. As mentioned above, blastocysts are more valuable than oocytes or early embryos. Blastocysts are also acknowledged to be superior in the prediction of the therapeutic effects of any regimen or protocol under study, and in terms of pregnancy outcomes. Furthermore, as this study was a retrospective cohort study, the related influencing factors, such as the oocyte retrieval cycles and the oocyte retrieval protocols of the two groups, were not completely controlled or consistent for either group. Consequently, using the quantity of oocytes as an indicator would have introduced bias and other challenges in the assessment and interpretation of the research outcomes. In this study, we retrieved 4,155 oocytes from 712 patients in the supplementation group, over the course of 1,523 ovarian stimulation cycles, with an average of 2.72 oocytes obtained per cycle. For the non-supplementation group, 1,746 oocytes were collected from 302 patients over 690 cycles, with an average of 2.53 oocytes obtained per cycle. This evidence was in line with our more long-term clinical observations, suggesting that DE-T1 could improve both the quality and quantity of oocytes.
Patients who struggled to attain successful oocyte retrieval and blastocyst culturing generally resorted to several cycles of oocyte retrieval, rendering their courses of treatment relatively long. We aim to explore optimal courses of supplementation for patients of differing ages and AMH values in the future, to enable us to prescribe individualized supplementation protocols for each patient.
In this study, we observed 1014 cases over an observation period of approximately 8 years. The supplementation group underwent a total of 1523 stimulation cycles. Using real-world research methodologies, we didn’t set any strict inclusion criteria for the participants. In consequence we suggest that the results of this study may more truly reflect the influence of DE-T1 on women with different ages and AMH values who receive IVF-ET treatment.
Reproduction is a complex physiological process. The mechanisms by which DE-T1 achieves its multi-target, synergistic influences on the hypothalamus, pituitary glands, ovaries, uterus and other organs requires further study.