Purpose <p>The objective of this study was to investigate the cumulative pregnancy, cumulative live birth, and perinatal and obstetric outcomes of individuals in the POSEIDON group, with the aim of enhancing the management of individuals receiving assisted reproductive technology (ART) who have characteristics associated with a poor prognosis.</p> Methods <p>In this study, 19,371 patients with infertility who underwent their first IVF/ICSI cycle at the Tongji Hospital from January 2016 to December 2021 were enrolled. The population was divided into 4 Poseidon subgroups (PG1-PG4) and a non-Poseidon (non-PG) group based on the POSEIDON criteria. The stratification is based on ovarian reserve and ovarian response to stimulation, with the goal of tailoring individualized stimulation strategies.</p> Results <p>The cumulative clinical pregnancy rate (CPR) gradually decreased from non-PG patients to PG 1–4 patients, with rates of 84.6%, 72.5%, 54.7%, 51.7%, and 30.7%, respectively. The cumulative live-birth rate (CLBR) was highest in non-PG patients, followed by PG1 patients, PG3 patients, PG2 patients, and PG4 patients, with rates of 81.0%, 67.0%, 45.3%, 45.2%, and 22.9%, respectively (p &lt; 0.001). Additionally, the PG patients did not differ from the non-PG patients in terms of perinatal and birth outcomes, except for a decrease in gestational age and birth weight and an increase in the rate of preterm births, gestational diabetes, and cesarean section.</p> Conclusions <p>Maternal age was the primary factor affecting pregnancy outcome. The younger subgroups (PG1, PG3) presented an acceptable CLBR (&gt; 50%) and were not associated with an increased risk of abnormal perinatal outcomes.</p>