Dual triggering fails to improve mature oocyte yield in poor responders: POSEIDON group 4 analysis

Final oocyte maturation triggering is a decisive step in controlled ovarian stimulation, and in poor ovarian responders even modest gains in oocyte yield can shift reproductive outcomes. Dual triggering, which combines human chorionic gonadotropin (hCG) with a gonadotropin-releasing hormone agonist (GnRHa), has been proposed as a way to improve oocyte yield and maturation. Evidence in poor responders, however, remains limited and inconsistent, likely because the populations studied are heterogeneous. Within the POSEIDON classification, group 4 patients—older women with reduced ovarian reserve—are a particularly relevant group for evaluating optimized stimulation strategies.

The authors conducted a retrospective cohort study of GnRH antagonist IVF cycles in POSEIDON group 4 women, defined as age 35 years or older with reduced ovarian reserve markers. The analysis was cycle-based, comparing cycles that used dual triggering against those using hCG alone. The primary focus was mature oocyte yield, the endpoint most directly tied to the rationale for dual triggering in this population.

The main finding was that dual triggering did not improve mature oocyte yield in these patients. Despite the biological rationale that adding a GnRHa surge might enhance final oocyte maturation, the cycle-based comparison showed no advantage over standard hCG triggering in POSEIDON group 4 women. This contrasts with some earlier reports in broader or mixed poor-responder populations, where dual triggering has occasionally been associated with better oocyte retrieval outcomes.

Several caveats apply. The study is retrospective, so selection bias and unmeasured confounders cannot be excluded, and treatment decisions were not randomized. The cycle-based design means results describe cycles rather than individual patients, which can affect interpretation when patients contribute more than one cycle. The findings are specific to POSEIDON group 4, a population defined by age and ovarian reserve, and should not be generalized to other POSEIDON groups or to poor responders as a whole without further study.

For laboratory and clinical researchers, this paper adds to a mixed literature on dual triggering and underscores the importance of stratifying by well-defined responder categories. It does not establish a clinical recommendation, and the results are intended for research context only. Further prospective or randomized work in narrowly defined poor-responder groups would help clarify whether any subgroup benefits from dual triggering.