Progesterone is the ovarian steroid produced by the granulosa cells of follicles after the LH peak at mid-cycle. Its role is to sustain embryo endometrial implantation and ongoing pregnancy. Other biological effects of progesterone may exert a protective function in supporting pregnancy up to birth. Luteal phase support (LPS) with progesterone is the standard of care for assisted reproductive technology. Progesterone vaginal administration is currently the most widely used treatment for LPS. Physicians and patients have been reluctant to change an administration route that has proven to be effective. However, some questions remain open, namely the need for LPS in fresh and frozen embryo transfer, the route of administration, the optimal duration of LPS, dosage, and the benefit of combination therapies. The aim of this review is to provide an overview of the uterine and extra-uterine effects of progesterone that may play a role in embryo implantation and pregnancy, and to discuss the advantages of the use of progesterone for LPS in the context of Good Medical Practice.

Artificial intelligence (AI) has been experiencing rapid growth in recent years, and numerous applications are improving the single-step efficiency of the whole assisted reproductive technology (ART) procedure. In this review, we collected all the algorithms supplying ART and selected those supporting the clinical assistance to the procedure up to the successful attempt. Those with a clear role in improving ART performances were further selected. We found a questionnaire-based algorithm identifying patients at risk for endometriosis with early management and better fertility outcome. An algorithm can detect the values of simple gamete production (male) and reservoir (female) according to gradual scale allocation, and display themas normal or abnormal, spontaneousor stimulated gamete production. This can provide significant benefits for infertile couples undergoing diagnostic and therapeutic journeys. The calculators for the starting dose of gonadotropins and the trigger timing during controlled ovarian stimulation make clinical management more efficient. With the application of AI in ART, the ability to determine the optimal number of metaphase II oocytes required for blastocyst formation and number of oocytes needed for embryo production has been significantly improved. The calculation of the implantation rate as proposed in different calculators, using the ultrasound of endometrial vascularization or the age and euploidy of the embryo transferred, may provide further advancement in managing the ART procedure with more participation from the couples to increase the efficacy of the procedures. Finally, the calculator of presumptive success with an ART program based on couples or medical center profiling and efficiency is of tremendous comfort to couples. In conclusion, algorithms and machine learning development in human reproduction are growing daily with evident benefits. Infertility treatments by in vitro fertilization (IVF) are assisted by several algorithms that improve the efficiency of each procedure step, making IVF program’s management more effortless.

Over the past two decades, fertility services have experienced significant shifts in ownership structures worldwide, transitioning from predominantly public or physician-owned clinics to a market increasingly influenced by private equity. These changes raise debates about treatment efficacy, cost transparency, and the ethical implications of profit-driven health care. This review provides an evidence-based overview of trends in fertility clinic ownership (public, physician-owned, and private equity-backed), along with reported success rates and implications for treatment quality, cost transparency, and patient well-being. A narrative synthesis was conducted using peer-reviewed literature, registry data, and industry reports published between 2000 and 2025 (projected). Ownership distribution, reported live birth rates, and financial transparency were examined. Regional studies, market analyses, and professional guidelines were used to infer trends when global data were unavailable. Ownership trends show a decline in public- and physician-owned clinics, with private equity projected to control up to 50% of fertility centers in some regions by 2025. Treatment efficacy improved across all clinic types, with live birth rate per in vitro fertilization cycle rising from ~25 – 30% in 2000 to ~35 – 45% by 2020 in younger cohorts; higher rates in private equity clinics may reflect patient selection and reporting variability. Cost transparency remains inconsistent, particularly in private equity networks where bundled pricing and aggressive marketing may obscure true costs and incentivize unnecessary add-ons. The consolidation of fertility centers under corporate ownership has reshaped reproductive health care. Ongoing concerns include pricing opacity, the clinical value of “add-on” treatments, and the ethical positioning of clinicians in profit-driven settings.

Endometrial preparation is crucial in in vitro fertilization (IVF) protocols to create optimal conditions for embryo implantation and pregnancy. Successful embryo nidation requires a receptive endometrium, which is influenced by factors such as endometrial thickness, hormonal environment, autocrine and paracrine growth factors, and the presence of resident and non-resident stem cells within the endometrium basalis. Synchronization between endometrial and embryonic development is also essential. Endometrial preparation, whether achieved through spontaneous cycles, natural cycles with minimal support, ovulation induction, or hormone replacement therapy (HRT), results from a combination of biochemical and biophysical conditions, each independent of the others. These conditions are difficult to pinpoint within a fixed period (Window of Implantation, WOI) using any specific examination due to the variability in estrogen and progesterone production rates, their metabolic clearance rates (MCR) when administered exogenously, and their metabolism when given systemically, topically, or orally. These variations also occur in different phenotypes and over different durations. Moreover, the synchronization of endometrial preparation with incomplete decidualization and the uncertain duration of the implantation window pose challenges. It is also unknown if there are compliance mechanisms similar to diapause seen in other species. This review aims to outline a clinical approach that, while not an absolute clinical recommendation due to the lack of definitive certainties, assists in understanding complementary phenomena and provides a useful orientation for clinical practice.