What is low ovarian response, how is it predicted and how is the stimulation strategy built? Learn about few eggs and the Bologna and POSEIDON concepts.
Low ovarian response is the ovaries developing fewer eggs than expected in IVF stimulation. This situation does not by itself determine the likelihood of pregnancy; but it requires the stimulation plan to be built around you and adjusted to the response. The information is general in nature and does not replace an individual medical assessment.
What is low ovarian response?
When hormone medicines that stimulate the ovaries are used, the same number of follicles does not develop in everyone. When the number of follicles that develop falls below what is expected, low ovarian response is spoken of. Current guidelines on this subject prefer the term "low response" to the formerly used "poor response"; the aim is to prevent the word from carrying an unnecessarily negative connotation about prognosis and safety.
Are low response and low ovarian reserve the same thing?
Response is an event that takes place during stimulation; reserve is a concept describing the stock of eggs remaining in the ovary. Low reserve is one of the common causes of low response, but not the only one. On the other hand, in someone whose reserve tests look low, the response to stimulation may be better than expected; the reverse can also be seen. The tests themselves and their interpretation are a separate subject.
Does the development of few eggs show that egg quality is low?
According to the current view on this subject, reserve indicators predict well the number of eggs that will come out of stimulation; their predictive power for egg quality and for the relationship with pregnancy or live birth is weak. Therefore the development of a small number of eggs does not show that the quality of those eggs is low. Age also has an effect on quality, and the result is considered together with age when it is assessed.
What do the Bologna and POSEIDON classifications mean?
Two frameworks are often mentioned for describing people with low response in a common language. They are not diagnostic documents or names of diseases, but classification tools.
Bologna criteria. An attempt, arising in 2011 from an expert consensus, to standardise low response. Its logic can be summarised as follows: the presence of several features together, such as advanced age or a similar risk factor, a low response obtained in a previous stimulation, or low reserve test results, is taken as the basis for the definition of low response. These criteria do not treat the number and the quality of eggs separately and can group people with very different characteristics in a single group; this is the most common criticism.
POSEIDON classification. This framework is not a guideline; it is a classification proposed in 2016 by a group of experts, based on the concept of "low prognosis". By assessing age, reserve indicators and, if there is one, the previous response together, it divides people with low response into subgroups. There are criticisms about its validation with real-life data. This framework is a supporting language that doctors use when describing a patient.
Both frameworks have threshold values; but these thresholds are interpreted from study to study and do not take the place of an individual decision. Whichever classification the doctor uses, what matters most is that the plan is built with data specific to you.
How is response predicted and monitored?
Current guidelines on this subject recommend the use of the antral follicle count or the AMH measurement to predict the response to stimulation. A prediction states a likelihood, not a certainty: the predicted response and the response that actually occurs may differ. After stimulation has started, the response is monitored with ultrasound and, when needed, hormone measurements. The response that actually occurs is the most direct information that determines how the doctor will adjust the plan in that cycle and in later cycles.
How is your medicine plan determined?
People with low response are not a uniform group; their ages, reserve indicators, previous responses and accompanying problems differ. For this reason a single medicine plan is not fitted to all of them. Your doctor adjusts the type and amount of stimulation medicines according to a plan determined for you and for the monitoring findings. Current guidelines recommend that a certain upper amount of medicine not be exceeded in people in whom a low response is predicted; that is, continually increasing the amount is not recommended as a solution.
Is a modified natural cycle suitable for everyone?
Approaches that make use of the body's own cycle come up from time to time. According to current guidelines, a modified natural cycle is probably not recommended routinely in preference to standard stimulation in people with low response; but because those with low response are a very varied group, this option can be considered by the doctor when the reserve is very low. That is, this approach is neither more suitable for everyone nor unnecessary for everyone.
If the response is low, is the treatment cycle cancelled?
A low response is not regarded as sufficient grounds on its own for cancelling a cycle. When the response during stimulation turns out lower than expected, whether to continue is decided together with your doctor, by talking about your expectations for pregnancy. Whether the decision to cancel or continue is the right one cannot be said beforehand; the decision is shaped by your individual circumstances, your age and your previous cycle history.
How does your age affect the interpretation of low response?
As age advances, low response is seen more often and egg quality is also affected. For this reason the same egg number can carry a different meaning at different ages. Age is a markedly stronger factor than reserve tests in predicting reproductive outcome. If your age is advancing, waiting with methods that have limited data support can lose time; for this reason it matters that the plan is made without delay.
Are additional medicines and supplements recommended in low response?
Various additional medicines and supplements are often offered to people with low response. Current guidelines do not recommend the use of DHEA in people with low response, and state that growth hormone and testosterone are also probably not recommended. These recommendations against rest mostly on insufficient data; they do not mean that harm has been proven, and they may change with new studies. Current assessments do not recommend routine use of most of the add-on procedures to IVF either. When one of these methods is recommended to you, it is sensible to ask your doctor what it rests on, and its benefits and harms.
Is pregnancy possible with few eggs?
According to the current view on this subject, reserve indicators do not determine pregnancy or live birth independently of age; for this reason collecting a small number of eggs does not mean that the likelihood of pregnancy is over. What the likelihood is varies from person to person and cannot be expressed by a general number. The quality of the eggs as well as how many there are, your age and your uterine environment also affect the outcome. A low AMH or a low follicle count does not mean "you will not be able to conceive", just as it does not mean "there will be no problem". You can talk about your expectations and the next steps with your doctor after each cycle.
What can you do if learning that few eggs have developed is hard on you?
Getting the news "few eggs" during stimulation, after weeks of preparation and expectation, can be a heavy disappointment. Blaming yourself or your partner is mostly unwarranted; part of the factors that determine the response relate to age and biology. Talking about expectations with the doctor and, if necessary, applying to a mental health professional makes the process easier.
Are there risks of treatment even if the response is low?
A low response does not mean that the risks related to stimulation will not be seen at all. Ovarian hyperstimulation syndrome (OHSS) and clotting within the vessels are possible, although rare. Because transferring many embryos increases the risk of multiple pregnancy, current guidelines recommend single embryo transfer regardless of age.
Frequently Asked Questions
If few eggs came in the previous cycle, will the next be the same?
The previous response is important information that your doctor takes into account when building the plan, but it cannot be said beforehand that the response will be the same in the next cycle. After a cycle it is appropriate to review the medicine plan, the frequency of monitoring and the goals, and to assess the results together with your doctor.
If I do not meet the Bologna criteria, am I not counted as a low responder?
The Bologna criteria are not a condition for diagnosis; the response to stimulation is assessed independently of these frameworks. For this reason not meeting the criteria does not rule out the possibility of few eggs developing in stimulation; consult your doctor about this.
What information should I take when I go to the doctor?
Taking the medicine plan of the previous cycles, the follicle counts at the monitoring ultrasounds, the number of eggs collected and the number that were mature, the results of fertilisation and embryo development, your reserve test reports and the operations you have had makes it easier for the plan to be rebuilt. These records can also reduce the unnecessary repetition of the same assessments.
If my AMH is low, is natural pregnancy possible?
The likelihood of natural pregnancy also depends on your age, the state of your tubes and uterus, your ovulation and your partner's semen analysis. You should talk to your doctor about how the test is to be interpreted.
Does the development of few eggs show that the quality of the eggs is low?
No. The number of eggs and their quality are separate concepts. Reserve indicators help in predicting number; their predictive power for quality and for the outcome of pregnancy is more limited.
Are low reserve and low response the same situation?
No. Reserve relates to the stock of eggs remaining, and response to the follicles that develop during stimulation. Low reserve can be one of the causes of low response; however, the tests and the response that actually occurs do not always coincide.
Does increasing the amount of medicine always give more eggs?
Continually increasing the amount is not recommended as a solution. In people in whom a low response is predicted, it is recommended that a certain upper amount not be exceeded; your doctor adjusts your medicine plan according to your monitoring results.
Is the treatment necessarily cancelled if the response is low?
No. A low response is not sufficient grounds for cancellation on its own. The decision to continue or cancel is made together with your doctor by talking about your age, your previous cycles and your expectations for pregnancy.
Is a modified natural cycle more suitable for everyone with low response?
No. It is probably not recommended routinely in preference to standard stimulation. In some situations where the reserve is very low, your doctor may consider this option.
Should I use DHEA or growth hormone?
DHEA is not recommended in people with low response; growth hormone and testosterone are also probably not recommended. These recommendations mostly rest on insufficient data; you should talk to your doctor about the benefit, harm and evidence.
If few eggs were collected, is the possibility of pregnancy over?
No. Few eggs does not mean that the possibility of pregnancy is over; however, it gives no assurance of the outcome either. Your age, egg quality and uterine environment are assessed together.
Does low response remove the risks of treatment completely?
No. OHSS and clotting within the vessels are possible, although rare. Transferring more than one embryo also increases the risk of multiple pregnancy.
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