Poor ovarian response (POSEIDON): treatment options
Some women, despite correct stimulation, yield few eggs at retrieval. This “poor ovarian response” is one of the most demanding situations in IVF, because it limits the number of available embryos.
To address it more individually, international experts developed the POSEIDON classification, which divides these patients into groups based on age, ovarian reserve and previous response.
What does “poor ovarian response” mean?
It means that, despite adequate ovarian stimulation, few eggs are collected — usually fewer than four. This may be due to low ovarian reserve, older age, or an unexpectedly low response despite good baseline markers.
The core problem is not only the number; it is that fewer eggs mean fewer embryos and therefore a smaller chance per cycle.
What is the POSEIDON classification?
The POSEIDON classification (2016) replaced the older, more rigid concept of “poor response” with the broader concept of “low prognosis”. It divides patients into four groups, combining two key criteria: age (under or over 35) and ovarian reserve (AMH and antral follicle count).
Its aim is practical: to create more homogeneous groups so that treatment and prognosis are properly individualized, rather than lumping every difficult case into one “basket”.
What are the four groups?
Group 1: women under 35 with good ovarian reserve but an unexpectedly poor or suboptimal response. Group 2: women aged 35 and over with good reserve but also an unexpectedly poor response.
Group 3: women under 35 with low ovarian reserve from the outset. Group 4: women aged 35 and over with low reserve. Groups 1–2 are the “unexpected” poor response, while 3–4 are the “expected” one. In general, groups 1 and 2 have a better prognosis than 3 and 4, where older age and low reserve coexist.
What treatment options exist?
The approach is individualized by group. Elements discussed include: tailoring the dose and type of gonadotropins, adjusting the protocol, and strategies to accumulate eggs or embryos over more than one cycle to raise the total number.
In selected cases, approaches such as DuoStim are considered for rapid accumulation. It is important to stress that no “miracle” supplement or add-on has been shown to reliably increase births in these patients.
How much does embryo accumulation help?
When each cycle yields few eggs, the idea is to perform more cycles, freeze the embryos and “accumulate” a satisfactory number before transfer or preimplantation testing. This raises the cumulative probability per patient.
This strategy requires patience and clear counselling: the aim is not a perfect response in one cycle, but the sum of several attempts.
What is the realistic message?
Poor ovarian response does not mean an inability to have children, but a lower prognosis that requires an individualized, patient strategy. The POSEIDON classification helps place you in the right group and hold realistic expectations.
When ovarian reserve is very low and attempts do not succeed, an honest discussion of alternative options — including egg donation — is part of responsible, humane care.
Summary
Poor ovarian response means few eggs despite correct stimulation, and therefore a lower prognosis. The POSEIDON classification divides patients into four groups by age and ovarian reserve, so that treatment can be individualized. Options include adjusting the protocol and strategies to accumulate embryos over several cycles; no “miracle” add-on has been proven. The realistic message is patience, individualization and, when needed, an honest discussion of alternatives such as egg donation.
⚕ Medically reviewed by Prof. Stratis Kolibianakis · Thessaloniki Medical Association Reg. No. 16340
ARTICLE 7 · IVF
