In modern assisted reproductive technology (ART), as in any medical specialty, individualized treatment is the optimal goal to counterbalance efficacy and safety with the implementation of different ART modalities, optimizing time to live birth. In general, patients embarking on ART treatment can be reassured that they have a relatively good prognosis of obtaining a live birth. Based on a total of 5165 patients from the ART registry in Denmark during the period 2007–2010, a recent study reported a cumulative live birth rate of 71% (95% CI; 70–72%) at 5-year follow-up from the start of treatment [
1]. Women aged < 35 years had an 80% live birth rate compared to 61% for women aged 35–39 years and 26% for women aged ≥40 years, emphasizing the importance of giving ART patients an age-stratified prognosis during counseling. With the exponential growth in technological advances, controlled ovarian stimulation (COS) remains the keystone of successful ART treatment, aiming at achieving multi-follicular development to obtain a good chance of transferring embryos with the highest implantation potential [
2]. In agreement with recent reports comparing individualized and conventional COS [
3,
4], most clinicians use ovarian reserve markers like antral follicle count (AFC) and/or Anti-Müllerian hormone (AMH) for clinical decision-making to tailor the most optimal individualized controlled ovarian stimulation (iCOS) strategy, securing the shortest time to pregnancy and live birth as well as a low risk of ovarian hyperstimulation syndrome (OHSS) development [
5]. Thus, efficacy, safety and patient friendliness have become the mantras of modern ART, introducing protocols which decrease OHSS to an absolute minimum without compromising live birth rates [
6,
7]. However, the clinical management of patients with poor ovarian reserve, so called poor ovarian responders (PORs) still remains a clinical challenge. This was further complicated by the fact that only until recently there was no general agreement about the diagnosis of POR. Thus, Polyzos and Devroey (2011) reported the use of as many as 41 different POR definitions in a total of 47 randomized controlled trials (RCT), which hampered the clinical value of interstudy comparison and meta-analysis in this heterogenous group of patients [
8]. In their title the authors provocatively asked whether there was any “light at the end of the tunnel for the POR patient”. Subsequently, in 2011, an ESHRE consensus group [
9] took the effort to try to standardize the definition of POR, establishing the so called ESHRE Bologna criteria (Table
1).
Table 1
The ESHRE consensus Bologna criteria for poor ovarian response (POR)
Advanced maternal age (≥40 years) or any other risk factor for PORa |
A previous POR (≤3 oocytes with a conventional stimulation protocol)b |
An abnormal ovarian reserve test (i.e. antral follicle count < 5–7 follicles or AMH < 0.7–1.3 ng/mL)a,c |
Now, 6 years later, we ask ourselves, whether the Bologna criteria really brought POR patients out of the tunnel and into the light? In this review, we discuss the recent advances in iCOS for POR patients following the introduction of the ESHRE Bologna criteria. Moreover, we introduce the new POSEIDON classification of the “low prognosis patient” [
10,
11], which was established with the primary objective of providing a more detailed stratification of expected low responders and to significantly reduce the heterogeneity seen in the Bologna POR population.