Clinical trials

Endometrial peristalsis may influence embryo implantation and pregnancy outcomes, but its role during hormone replacement therapy (HRT)-prepared frozen embryo transfer (FET) cycles remains unclear. This prospective observational study will assess endometrial peristalsis at predefined time points during HRT-prepared FET cycles using transvaginal ultrasonography and evaluate its association with pregnancy outcomes. The study aims to clarify the clinical significance of endometrial peristalsis in HRT-prepared FET cycles and to provide evidence supporting endometrial assessment in assisted reproductive technology.

This randomized clinical trial aims to assess the comparative effectiveness of two distinct endometrial preparation protocols for frozen embryo transfer (FET) among women with adenomyosis undergoing IVF/ICSI. Specifically, it seeks to address the following key questions: 1. Does the protocol involving the combination of GnRH agonist and letrozole for down regulation with exogenous steroids (GnRHa+AI - AC) result in a higher live birth rate compared to the use of exogenous steroids alone (AC) in women with adenomyosis undergoing frozen embryo transfer? 2. What are the common side effects of the GnRHa+AI - AC regimen? Eligible participants will undergo screening before endometrial preparation for FET, following which they will be randomly assigned to one of two groups: GnRHa+AI - AC or AC. In the GnRHa+AI - AC group, participants will be pre-treated with GnRH agonist and letrozole two months before endometrial preparation. After this period, participants will return for endometrial preparation, and any side effects resulting from the down regulation will be evaluated. In contrast, the AC group will receive standard treatment.

The goal of this clinical trial is to learn if biphasic In Vitro Maturation (IVM) works to help young women who produce very few oocytes after controlled ovarian stimulation. The study focuses on women under age 35 who have a good number of follicles in their ovaries but do not respond well to standard ovarian stimulation by Gonadotropin (known as POSEIDON Group 1a). The main questions it aims to answer are: How many mature oocytes can be obtain after biphasic -VM? Researchers will use biphasic-IVM system to see if it can bypass the problems these patients face with standard treatments, such as high costs and the risk of medical complications like Ovarian Hyperstimulation Syndrome (OHSS). Participants will: Have their immature eggs collected from the ovaries without the need for high-dose hormone injections. Have their eggs matured in a specialized laboratory using a two-step process (biphasic IVM) to improve egg quality. Follow up with researchers to check the number of embryos created and the safety of the procedure.

The uterus is a dynamic muscular organ that undergoes rhythmic, wave-like contractions known as endometrial peristalsis or endometrial waves. This muscular activity, which is an essential component of natural fertility, presents a nuanced and sometimes contradictory role in the context of assisted reproductive treatments. Endometrial peristalsis refers to the frequency, amplitude, and pattern of myometrial contractions occurring in different reproductive phases. These peristalsis play vital roles in sperm transport, embryo migration, and implantation. Clinical and imaging studies suggest that abnormal patterns or excessive contractility at the time of embryo transfer may disrupt endometrial-embryo synchrony, impair implantation, and increase miscarriage risk. However, most evidence on endometrial peristalsis pertains to fresh embryo transfer cycles, natural conceptions, or pathological contexts, such as adenomyosis or fibroids, with limited insights regarding its effects on different endometrial preparation protocols in frozen embryo transfer (FET). Understanding the dynamics of endometrial peristalsis in this context is clinically important, as inappropriate contractile activity could physically expel the embryo or create a non-receptive environment, ultimately reducing the chances of live birth. Despite its theoretical significance, there is a paucity of robust, prospective data correlating endometrial peristalsis patterns measured around the time of FET with different endometrial preparation protocols with subsequent pregnancy outcomes.

Subclinical hypothyroidism (SCH) is defined by elevated thyroid-stimulating hormone (TSH) with normal free thyroxine (fT4) levels. It affects approximately 5-7% of women of reproductive age and may negatively influence outcomes of assisted reproductive technology (ART). During controlled ovarian stimulation, rising estradiol increases thyroxine-binding globulin and thyroid hormone requirements. These physiological changes, combined with increased metabolic demand in early pregnancy, may worsen SCH and contribute to adverse outcomes such as miscarriage, preterm birth, and hypertensive disorders of pregnancy. Although levothyroxine (LT4) is routinely used to treat overt hypothyroidism, evidence for its benefit in SCH, especially among infertile women undergoing In Vitro Fertilization (IVF) or Intra-Cytoplasmic Sperm Injection (ICSI) with frozen embryo transfer (FET), remains inconclusive. Some trials and meta-analyses have shown reductions in miscarriage and neonatal mortality, while others have found no improvement in ART or obstetric outcomes. This study aims to evaluate the effectiveness of levothyroxine therapy on IVF/FET outcomes and subsequent pregnancy results in women with subclinical hypothyroidism and infertility. This retrospective cohort study will emulate the target trial to evaluate whether LT4 treatment, titrated to achieve a pre-transfer TSH \< 2.5 mIU/L, improves implantation, live birth, and obstetric outcomes compared with expectant management.

Capacitation in vitro maturation (CAPA-IVM) has improved oocyte maturation and resulted in live births. Because cumulus cells (CCs) communicate bidirectionally with the oocyte, their transcriptomic profile may serve as a non-invasive biomarker of oocyte and embryo competence. This prospective pilot study will analyze CCs gene expression after CAPA-IVM using RNA sequencing and pathway analysis, and correlate findings with embryological outcomes including fertilization, day-3 cleavage, and blastocyst formation. Results are expected to provide insights into the molecular basis of oocyte competence and support development of non-invasive embryo selection strategies.

Assisted Reproductive Technologies (ART) aim to increase success rates while minimizing patient risks. For women with high AFC or PCOS, conventional IVF carries a high risk of OHSS (Ho et al., 2019). A modern IVF strategy to prevent this uses a GnRH agonist trigger, requiring a "freeze-all" and subsequent FET (Wong et al., 2017). This reduces OHSS risk but can increase time to pregnancy (Vuong et al., 2021) and treatment burden. IVM is a patient-friendly alternative that eliminates OHSS risk by avoiding high-dose gonadotropins. A 2020 trial by Vuong et al. compared CAPA-IVM-FET to conventional IVF-FET in women with high AFC. IVM yielded a comparable live birth rate (35.2%) versus IVF (43.2%), with a 0% OHSS rate in IVM compared to 0.7% in IVF (Vuong et al., 2020). The optimal transfer method (fresh or frozen) in IVM cycles is debated. A 2021 pilot RCT by Vuong et al. found a freeze-only strategy after CAPA-IVM led to a significantly higher live birth rate (60%) than a fresh transfer (20%) (Vuong et al., 2021), but increased time to pregnancy (194 vs. 150 days) (Vuong et al., 2021). A refined CAPA-IVM protocol, which uses no gonadotropins, allowed for fresh embryo transfer in the same cycle, resulting in a numerically higher ongoing pregnancy rate (43.3% vs. 33.3%) than FET (Vuong et al., 2025). This raises an important question: how does a simplified IVM strategy with fresh transfer compare to the established "safety-net" IVF strategy with FET? These two approaches represent opposing clinical philosophies. No large-scale study has yet compared them in women with PCOS. Therefore, this study is designed to compare the SAIGON protocol (gonadotropin-free CAPA-IVM with fresh ET) against a standard GnRH-antagonist IVF protocol with agonist trigger and subsequent FET.

The goal of this randomized clinical trial is to evaluate the effectiveness of the letrozole-stimulated cycle strategy versus the artificial cycle strategy for endometrial preparation in women with irregular menstrual cycles after one cycle of endometrial preparation. The primary question it aims to answer is: • Does the letrozole-stimulated cycle strategy for endometrial preparation result in a higher live birth rate compared to the artificial cycle strategy in women with irregular menstrual cycles after one cycle of endometrial preparation? Participants will undergo screening before endometrial preparation for frozen embryo transfer, following which they will be randomly assigned to one of two groups: LETS or AC. In the LETS group, investigators will prescribe letrozole 5 milligrams/day for 5 days to stimulate follicular development and micronized progesterone 800 milligrams/day for luteal phase support. In contrast, the AC group will receive oral estradiol valerate 6-12 milligrams/day and micronized progesterone 800 milligrams/day. Researchers will compare the LETS and AC groups to determine if there are differences in live birth rates.

The female genital tract microbiome may reflect female reproductive health and may be related to pregnancy outcomes. Disturbances in this microbiome may be associated with adverse reproductive outcomes. The investigators hypothesize that the endometrial and vaginal microbiome composition in women with a history of recurrent pregnancy loss are different, compared with those in normal fertile women.

The multi-step thawing protocol with a reduction of non-permeable cryoprotectant concentrations to reduce osmotic shock caused by the rapid influx of water. Recent studies have shown that a simplified warming protocol by only a thawing solution gave a comparable survival rate but increased pregnancy rate, reduced patients' waiting time, and decreased the workload of embryologists.

This study compares the effectiveness of cervical cerclage with vaginal progesterone to vaginal progesterone only for the prevention of preterm birth in women with a singleton pregnancy and a short cervical length. Participants will be randomly assigned in a 1:1 ratio to receive cerclage plus progesterone or progesterone only.

The efficacy and safety of endometrial preparation regimens remain controversial. In the most recent meta-analysis, using natural and modified natural cycle protocol to prepare the endometrium in frozen embryo transfer resulted in higher live birth rates. In addition, the natural cycle reduces the risk of gestational hypertension, postpartum haemorrhage, and extremely preterm delivery compared with regimens using exogenous hormones. Because there are many physiological and endocrinal differences in the frozen embryo transfer cycle with different endometrial preparation protocols, the development of children born from these regimens has received much attention. For example, there is a complete absence of the corpus luteum during the cycle of exogenous hormone administration. Or in the modified natural cycle, the pharmacokinetics is not entirely the same as the natural physiology when using an additional ovulatory injection with hCG. To date, there have been no longitudinal follow-up studies that evaluated and compared the long-term development of IVF/ICSI children born from frozen embryo transfer with different endometrial preparation protocols. Thus, the investigators conduct a follow-up of our RCT to investigate the IVF/ICSI children born from frozen embryo transfer with different endometrial preparation protocols to give strong evidence about the safety of the three most common endometrial preparation protocols in women undergoing frozen embryo transfer.

This randomized controlled trial (RCT) aims to evaluate whether, in infertile women with WHO II/IV ovulatory disorders, a combination of letrozole (LE) and clomiphene citrate (CC) compared to LE alone, result in higher live birth rates. The study is designed as an open-label, multicenter RCT across six fertility clinics in Vietnam. Participants will be randomized into two groups: (1) LE + CC , (2) LE alone. The primary outcome measure is the live birth rate after one treatment cycle. Based on prior data, the live birth rate for IUI in letrozole cycles is estimated at 12%. To detect a 10% increase in live birth rates with CC, 436 couples are needed (α = 0.05, power = 80%). Additionally, the live birth rate after IUI with LE-induced ovulation is approximately 18.7% (Diamond et al., 2015). To detect a 10% increase with CC, 560 couples are required (α = 0.05, power = 80%). Considering a 5% loss to follow-up and protocol deviations, the study plans to recruit 600 participants (150 per arm).

CAPA-IVM (In Vitro Maturation) technology is an assisted reproductive method offering significant benefits in terms of safety and treatment costs, particularly for high-risk patients. These include individuals with ovarian hyperstimulation syndrome (OHSS), venous thrombosis, ovarian torsion, or polycystic ovary syndrome (PCOS). However, while the live birth rate in the CAPA-IVM group (35.2%) is comparable to conventional IVF (43.2%), the number of good-quality embryos and cumulative clinical pregnancy rates remain lower. Improving the CAPA-IVM culture process, particularly through the addition of growth factors found in follicular fluid, has shown promise in enhancing oocyte quality. Growth differentiation factor 9 (GDF9) and Bone morphogenetic protein 15 (BMP15) play critical roles in follicular development, with their heterodimer structure demonstrating the most positive effects on cumulus-oocyte complexes (COCs). Recent studies have identified a potent variant, super GDF9, which is \>1000 times more effective than GDF9 and surpasses cumulin, a heterodimeric growth factor. Super GDF9 enhances cumulus cell expansion and oocyte developmental competence, closely mimicking in vivo maturation. This study investigates the impact of supplementing super GDF9 during CAPA-IVM culture, aiming to improve outcomes of cumulus-oocyte complexes (COCs) from small follicles and ultimately enhance treatment success.

In vitro maturation (IVM) is an assisted reproductive technology (ART) using minimal or no ovarian stimulation. In IVM, immature oocytes at the germinal vesical (GV) or metaphase I (MI) stage retrieved from small antral follicles are cultured to reach metaphase II (MII) (ASRM, 2021). Since the first successful IVM baby was reported, subsequent studies have been mostly focused on patients with polycystic ovary syndrome (PCOS) to reduce the risks associated with ovarian stimulation such as ovarian hyperstimulation syndrome (OHSS), thromboembolic complications and ovarian torsion (Cha et al., 1991; Chian et al., 2000). Numerous IVM protocols have been applied with or without FSH or hCG priming and using one step or two steps culture system to gain the optimum oocyte maturation rate, blastulation rate and live birth rate (Sanchez et al., 2019; De Vos et al., 2021). A randomized controlled trial (RCT) conducted on women with high antral follicle count, including women with PCOS, indicated that CAPA-IVM was non-inferior to conventional IVF (Vuong et al., 2020). Studies also showed that the mental and motor development of children born after IVM was similar to that of those born after IVF and naturally conceived (Nguyen et al., 2022; Vuong et al., 2022). Additionally, IVM is considered an effective treatment for women with gonadotropin resistant ovary syndrome to have children with their own oocytes (Le et al., 2021). IVM is also a viable option for fertility preservation for women with cancer in need of urgent treatment and contraindicated to hormonal stimulation (Grynberg et al., 2022). There is little evidence on the effectiveness of IVM on women without PCOS. Junk et al have compared the effectiveness of IVM between women with polycystic ovaries (PCO) and polycystic ovary syndrome (Junk and Yeap, 2012). Women with PCO had significantly lower oocytes collected than those with PCOS (p\<0,001), maturation rate, blastocyst development rate, and clinical pregnancy rate were comparable between two groups (Junk and Yeap, 2012). Another study indicated the maturation rate after standard IVM of ovarian tissue-derived oocytes collected from cancer patients was 8-67% (Segers et al., 2020). A study conducted by Kirillova on ovarian cancer patients with normal to high ovarian reserve showed that CAPA-IVM resulted in a higher maturation rate in ovarian tissue oocytes compared to standard IVM (56% vs 36%, p=0.0045) (Kirillova et al., 2021). Recently, IVF/ICSI has been indicated in almost all infertility patients without PCOS. A randomized controlled trial on non-PCOS women with high antral follicle counts revealed no significant differences between IVM and conventional IVF regarding the ongoing pregnancy rate, live birth rate and the incidence of pregnancy and perinatal complications (Vuong et al., 2020). IVM offers numerous advantages due to the concept of using mild or no stimulation. The risk of ovarian hyperstimulation syndrome is largely eliminated, the cost of treatment is notably reduced. IVM is also more convenient as it requires fewer patient visits, ultrasounds and blood tests (Ho and Vuong, 2023). Therefore, this pilot study is to evaluate the effectiveness and safety of CAPA-IVM in ovulatory infertile women and evaluate its success rate in relation to their ovarian reserve.

Lipiodol® flushing is an effective fertility treatment for women with unexplained infertility. It is speculated that the treatment effect could work through a direct effect of Lipiodol® on the endometrium. Given this direct effect on the endometrium, it is further hypothesized that Lipiodol® uterine treatment prior to In Vitro Fertilization (IVF)/ Intracytoplasmic Sperm Injection (ICSI) may also improve pregnancy rates. However, the effectiveness of Lipiodol® as an adjunct to IVF/ICSI treatment has not previously been examined in a well-powered and properly conducted randomised clinical trial.