When Dr. Rui Wang and his team at the University of Sydney went looking for evidence behind one of the most widely offered IVF add-ons, they expected to confirm what earlier studies had suggested. Instead, they found something that could change how fertility clinics worldwide approach patient care. Their analysis, published in Human Reproduction Update, shows that intrauterine administration of human chorionic gonadotropin (hCG) before embryo transfer does not improve pregnancy or live birth rates — a finding that contradicts years of clinical practice. The procedure, used in Australia, the United States, Europe, and parts of Asia since the early to mid-2010s, has been promoted to improve implantation during IVF based on earlier research that reported positive effects. But when Wang's team examined the raw data behind those studies rather than relying on published conclusions, the benefits vanished. "For patients and clinicians, the message is clear: this add-on does not improve fertility outcomes," Wang said. "This hormone shouldn't be routinely offered as part of IVF treatment." The researchers conducted an individual participant data meta-analysis — the gold standard for evidence synthesis — collecting and reanalyzing raw, de-identified data from every patient involved in clinical trials on this topic. Of 28 randomized trials conducted across the United States, Austria, Thailand, and Japan, seven high-quality trials involving 2,244 IVF patients met the criteria for analysis. The team found no evidence of benefit in any subgroup they examined: fresh or frozen transfers, different embryo stages, or different doses. "When we restricted the analysis to studies where the raw data could be reviewed and verified, the effect disappeared completely," Wang said. The findings reveal a troubling pattern: many trials reporting positive effects failed basic trustworthiness checks. Earlier reviews had called intrauterine hCG one of the most promising IVF add-ons, and those conclusions influenced clinical practice worldwide. In Australia, the procedure typically costs $50 to $100 per cycle — modest compared to the overall cost of IVF, but adding an intervention with no proven benefit compounds the financial and emotional burden on patients already navigating a difficult journey. "Every procedure offered to patients should be backed by reliable evidence," Wang said. "When patients are already going through multiple IVF cycles, adding procedures with no proven benefit is an unnecessary burden on people navigating an already difficult journey." Wang believes this study could be just the beginning. The team hopes their methods — rigorous reanalysis of raw data rather than reliance on published summaries — might become the standard for evaluating other fertility add-ons that have slipped into clinical practice based on incomplete or unreliable evidence. "Patients deserve access to accurate, reliable evidence," Wang said. "This study is about supporting informed decision-making, not blaming clinics or patients." By bringing transparency to a corner of medicine where hope and uncertainty often collide, Wang and his colleagues are giving future patients something equally valuable as a treatment: the confidence to ask harder questions.