Embryo Transfer

Adenomyosis is associated with impaired endometrial receptivity and reduced implantation rates in assisted reproduction, even when using high-quality embryos. Linzagolix (Yselty, 200 mg) is an oral GnRH receptor antagonist approved for uterine fibroids with a favourable tolerability profile and rapid elimination half-life (18-20 hours) compared to GnRH agonists. This prospective case series evaluates the efficacy of linzagolix 200 mg administered for 3 to 6 months prior to embryo transfer in patients with confirmed adenomyosis and recurrent implantation failure (RIF), defined as ≥2 failed transfers with high-quality blastocysts (≥BB Gardner in oocyte donation, or PGT-A confirmed euploid in autologous cycles). The primary endpoint is the live birth rate (LBR) per embryo transfer. Secondary endpoints include clinical pregnancy rate, miscarriage rate, morphological response of adenomyosis (uterine volume and junctional zone \[JZ\] thickness assessed by standardised transvaginal ultrasound), and tolerability profile. The study also explores the optimal treatment duration (3 vs 6 months) as a sub-analysis based on morphological response at the month-3 visit. The study is conducted at three centres of Vida Fertility Institute (Madrid, Alicante and San Sebastián, Spain). Sample size: n=35 patients. Study duration: 24 months.

Infertility is defined as the inability to conceive within a year of unprotected intercourse. Infertility affects one in six couples and represents a public health problem causing feelings of helplessness, depression, and anxiety in both women and men worldwide. Despite the desire to become parents, up to 50% of infertile couples do not seek medical treatment, and 50-60% abandon treatment after two or three failed in vitro fertilization (IVF) cycles, even when the procedure is covered by insurance or public health. There are multiple reasons for this discontinuation; however, after removing cost considerations, psychological stress and poor prognoses represent the main reasons for stopping treatment. Clinical infertility treatments are generally ineffective. Success remains poor even with IVF, as evidenced by current live birth rates (LBRs) of only \~30% per initiated cycle. The primary challenge in ART lies mainly in the embryo implantation process, which remains the most significant bottleneck in IVF success, accounting for over 50% of ART failures. Embryo transfer (ET), the final step in IVF, has seen little technological advancement since its inception over four decades ago. The procedure is typically performed transcervically and largely relies in tactile sensation and operator's experience. Although a simple procedure, several potential negative factors may be linked to the low number of IVF pregnancies, including variations in catheter placement, the risk of uterine contractions and lack of control of intrauterine pressure and embryo placement can result in up to 15% of the transferred embryos being inadvertently expelled from the uterus. Therfore, ET's success is highly dependent on non-controllable variables as well as the skill and experience of the operator, resulting in significant inter-operator variability. Premium Fertility team has developed a controlled embryo transfer system - the Transfer Direct System (TDS) - that incorporates a visualization system to guide embryo delivery with the help of a fully automated microfluidic system that avoids initial phases of apposition and adhesion of implantation of human embryos. This technique places the embryo directly in the endometrial tissue, thereby minimizing the effects of embryo expulsion and potentially offering significant advantages such as the ability to visualize the uterine cavity through an endoscope at the time of embryo transfer and control the mechanics of the injection procedure to increase precision.

The aim of this work was to investigate the effect of different vasodilators as pentoxifylline in women with unexplained infertility using IVF

Analysis of proteins from cervical mucus will be done in patients undergoing infertility treatment (fresh or frozen embryo transfer). Cervical mucus will be analysed for potential new biomarkers of endometrium receptivity. Comparison of the peptide spectrum will be done for the pregnant and not pregnant patients.

The rise in frozen embryo transfer (FET) cycles within assisted reproductive technology (ART) has sparked the need to refine endometrial preparation protocols. The switch from hormone replacement cycles (HRT) to natural cycles, poses scheduling challenges onto laboratories, doctors and patients. The modified natural cycle (mNC), offering more precision for scheduling, shows promise but lacks comprehensive data on the potential flexibility of triggering criteria that may allow to control timing in a wider range. This prospective randomized study seeks to address this knowledge gap by evaluating the non-inferiority of triggering ovulation in mNC with follicle diameters of 13-16.9mm compared to the conventional 17-22mm. The study aims to enhance the understanding of the impact of follicle size at ovulation in reproductive outcomes, optimize FET treatments providing a more flexible mNC protocol, and improve patient care in ART clinics.

Impact of dual trigger using recombinant human chorionic gonadotropin (HCG) and gonadotropin-releasing hormone (GnRH) agonist on thawed modified natural cycle outcomes: an open-label multi-center randomized controlled trial.

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.

In pregnancies achieved through programmed frozen embryo transfer cycle (PC-FET) and modified natural frozen embryo transfer (mNC-FET), to determine whether there are differences in endothelial and placental function, maternal cardiovascular function, fetal growth and fetal cardiovascular and cerebral programming and to assess whether there is an association between these differences and the plasma concentrations of the main secretion products of the Corpus Luteum (CL) with vasoactive and angiogenic action.

Title: A prospective multicentric interventional randomized controlled trial to assess the effect of low dose acetylsalicylic acid as a preventive treatment of pre-eclampsia in pregnant women who underwent frozen embryo transfer

The goal of this clinical trial is to test whether sexual intercourse the night after embryo transfer affects thawed embryo implantation rates. Women undergoing one of their first four frozen embryo transfers with a good quality embryo will be randomly assigned to two groups. The study group is subjected to have intercourse without using a condom at the evening/night after the embryo transfer, while the control group will abstain from intercourse for the next 48 hours after the transfer. Researchers will compare the ongoing pregnancy rates between the intervention group and the control group.