New insights into management of poor prognosis patients (POSEIDON Classification)

Robert Fischer's lecture addresses why the familiar label of the poor responder no longer reflects clinical reality and what the POSEIDON classification offers in its place. For years, patients with an inadequate response to stimulation were grouped into a single heterogeneous category, which made it hard to compare protocols or predict outcomes. The lecture shows how shifting the focus from the ovarian response itself to the prognosis of the outcome reshapes the way these patients are managed.

The first part covers the history behind the POSEIDON criteria (Patient-Oriented Strategies Encompassing IndividualizeD Oocyte Number). An international expert group formulated these criteria to move away from the vague definitions of poor response that had relied mainly on the Bologna criteria. The central idea was to describe a patient not by a single failed stimulation cycle, but by the combination of ovarian reserve markers, age and any previous response.

The core of the talk is the division of patients into four POSEIDON groups. It rests on three parameters: the woman's age (with a conventional cut-off around 35 years), ovarian reserve indices (AMH and antral follicle count) and, where available, the actual response to a previous stimulation. Combining these features separates so-called unexpected poor responders with normal reserve from predictably difficult patients with diminished reserve, allowing a more precise choice of protocol and gonadotropin dose.

Particular attention is given to the conceptual shift from response to stimulation toward prognosis of outcome. POSEIDON introduces the notion of low prognosis rather than low response and proposes, as a reference point, the ability to obtain at least one euploid embryo suitable for transfer. This links laboratory and clinical goals: what matters is not the follicle count in itself, but the probability of live birth that this count supports given the patient's age.

From this logic follow practical implications for management. For each group the lecture discusses a rational starting dose, the case for adding LH activity, strategies aimed at increasing the number of oocytes retrieved, and the role of accumulating embryos across several cycles. The emphasis is on individualising the plan so as to obtain enough mature oocytes to give a realistic chance of success.