Infertility

POI, POF, POR, DOR, FOR, TOR, Oh My! A Guide to Ovarian Reserve Acronyms

Halle Tecco
Halle Tecco, MPH, MBA
Last updated: January 15, 2026
an abstract painting with orange

Decoding the mysteries of infertility can sometimes feel like navigating a maze of medical jargon — POI, POF, POR, DOR, FOR… it can be enough to make your head spin. The journey is often filled with complex terminologies and a multitude of acronyms like these, making the process feel even more overwhelming than it already is. 

Each of these acronyms represents a distinct condition or factor that can influence fertility, and understanding them is vital to making informed decisions about your reproductive health.

These acronyms pertain to various ovarian conditions that can contribute to infertility, each with their unique challenges and treatment considerations. Though these conditions can introduce obstacles on the journey to parenthood, modern advancements in reproductive medicine provide promising solutions. In particular, egg donation stands as a beacon of hope for many individuals and couples navigating these challenges.

This article is designed to guide you through the intricacies of these terms, what they signify, their implications, prevalence, and treatment options. Whether you’re just starting your journey or are already deep into exploring infertility treatments, understanding these terms can empower you to make informed decisions about your reproductive health.

POI – Premature Ovarian Insufficiency

What is Premature Ovarian Insufficiency

Premature Ovarian Insufficiency, or POI, is a condition where a woman’s ovaries stop functioning normally before she reaches 40. This results in decreased fertility due to a lower production of eggs, irregular periods or even cessation of menstrual cycles. 

What causes Premature Ovarian Insufficiency

The causes can be varied, from genetic disorders to autoimmune diseases, and even certain treatments like chemotherapy. In cases of POI, the option of using donor eggs is a viable solution, as it bypasses the issue of egg production, providing a chance at successful conception.

Prevalence of Premature Ovarian Insufficiency

POI affects approximately 1% of the general population

How Premature Ovarian Insufficiency is treated

There is no cure for POI, but there are several treatment options available. Hormone replacement therapy (HRT) can help alleviate symptoms of menopause and reduce the risk of osteoporosis and heart disease. Those with POI who wish to conceive can also explore fertility treatments like in vitro fertilization (IVF) with donor eggs. Not only can this option (of course) assist with egg quantity, but donor eggs also come from women who are likely to have higher quality eggs and produce healthy embryos.

POI – Primary Ovarian Insufficiency

Primary Ovarian Insufficiency means the same thing as Premature Ovarian Insufficiency: when the ovaries stop functioning normally before age 40. When talking about POI, “Primary Ovarian Insufficiency” is the preferred acronym over “Premature Ovarian Insufficiency” by the National Institutes of Health, because ovarian function is unpredictable in many cases. Also, since 5–10% of women with POI experience unassisted pregnancy, POI is different from menopause, when unassisted pregnancy is impossible. 

POF – Premature Ovarian Failure

Premature Ovarian Failure (POF), also often used interchangeably with POI, is a condition where the ovaries cease to function before the age of 40. In 2016, the New European Society of Human Reproduction and Embryology (ESHRE) proposed using the term “premature ovarian insufficiency” instead for research and clinical practice. 

POR – Poor Ovarian Response

What is Poor Ovarian Response

Poor Ovarian Response is a condition characterized by an inadequate response to ovarian stimulation during assisted reproductive procedures, such as In-Vitro Fertilization (IVF). Those with POR produce fewer eggs even when given fertility drugs designed to stimulate egg production. This condition reduces the chances of successful IVF due to the lower number of eggs available for retrieval and fertilization. 

Prevalence of Poor Ovarian Response

The estimated prevalence of POR ranges from 6% to 35%. This wide range is primarily due to researchers and clinicians having varying definitions of POR. 

How Poor Ovarian Response is treated

Different strategies are employed to manage POR, such as using different protocols or higher doses of fertility drugs. There is some evidence that DHEA and CoQ10 may improve IVF pregnancy rates for those facing POR as well as some evidence that treatment with growth hormone (GH) for POR patients could lead to a higher number of retrieved eggs. In certain cases, fertility doctors may recommend alternative approaches such as the use of donor eggs or embryo adoption. These options can increase the chances of success by (ideally) giving you more healthy embryos to work with over a shorter period of time.

DOR – Diminished Ovarian Reserve

What is Diminished Ovarian Reserve

Diminished Ovarian Reserve refers to a decrease in the quantity of eggs. This condition is often related to aging, as the number of eggs declines naturally over time, but it can also occur prematurely in some. 

Prevalence of Diminished Ovarian Reserve

Between 10% to 30% of people who seek help for infertility have DOR.

How Diminished Ovarian Reserve is treated

Fertility treatments like IVF may be employed, but success rates can be lower due to fewer eggs. Depending on your family-building goals and timeline, the use of donor eggs from a younger, healthy donor can improve embryo fertilization outcomes by providing more eggs, in addition to significantly increasing the likelihood of pregnancy and reducing the risk of miscarriage.

FOR – Functional Ovarian Reserve

What is Functional Ovarian Reserve

Functional Ovarian Reserve refers to the number of responsive follicles in the ovaries at a given time. It is frequently used synonymously with the term ‘ovarian reserve’. Several research groups have used markers such as hormone levels or Antral Follicle Count (AFC) of follicles with diameters between 2-10 mm to measure FOR. Therefore, it seems that FOR is the term used to represent a biological quantification of the ovarian reserve. It is different from the diagnosis of Diminished Ovarian Reserve (DOR), which is based on a low Antral Follicle Count and/or hormonal indicators of reduced ovarian reserve.

Total Ovarian Reserve (TOR):

What is Total Ovarian Reserve

The Total Ovarian Reserve refers to the total number of immature eggs (primordial follicles) in the ovaries. This reserve is established at birth, decreases naturally with age, and can be influenced by certain medical conditions or treatments. 

Prevalence of Total Ovarian Reserve

A decline in TOR is a normal part of aging. However, some patients may experience a faster-than-normal decline due to conditions like POI or POF.

How Total Ovarian Reserve is treated

There is currently no proven method to increase the TOR since the number of eggs is established before birth. Fertility treatments aim to make the best use of the existing reserve and include ovulation induction, in-vitro fertilization (IVF), and in many cases, the use of donor eggs. Donor eggs provide a significant benefit for those with a low TOR, offering more eggs— and because they come from young, healthy donors, they increase the chance of a successful pregnancy. 

Create a free account to find your perfect egg donor today

What do these acronyms have in common? The “O.”

The unifying thread that weaves these acronyms together is the letter “O,” representing “Ovarian.” This commonality underlines the critical role the ovaries play in the reproductive system. Ovaries are responsible for egg production, crucial for the conception and reproduction process. Any disruption or disorder affecting the ovaries can have significant impacts on a woman’s fertility.

Ovarian function

In conditions like POI and POF, the issue arises from an early cessation or significant decrease in ovarian function. The ovaries prematurely reduce their activity, leading to a limited supply or a complete lack of viable eggs.

Ovarian response

With POR, the ovaries do not respond adequately to fertility treatments designed to stimulate egg production. This poor response leads to fewer eggs being produced than expected, reducing the success rates of assisted reproductive techniques such as IVF.

Ovarian reserve

DOR, TOR, and FOR are all about the ‘reserve’ of eggs in the ovaries. They refer to the quantity of the eggs a woman has left. DOR is a decrease in the amount or quality of the eggs, TOR refers to the total number of immature eggs (primordial follicles) in the ovaries, and FOR refers to the number of responsive follicles or eggs that can potentially be fertilized.

These acronyms all point to various challenges related to the ovaries that can influence fertility. Understanding these terms allows for more informed discussions with healthcare professionals about potential treatment strategies.

What is the success rate of donor egg IVF?

Donor egg IVF has the highest success rate of any fertility treatment, and using donor eggs can drastically increase your chances of success. 

At every age, the chances of birth with donor eggs is better, but those who benefit the most from donor eggs are women over 35 and those with low ovarian reserve. In fact, about one-quarter of women over 40 who succeeded with IVF did so through the use of donor eggs. 

At Cofertility, for those who match with a donor in our fresh egg donation program, the average number of mature eggs a family receives and fertilizes is 12. The number of eggs retrieved varies by patient and cycle, but can be predicted by a donor’s age, AMH, and antral follicle count, all of which will be known to you after the donor’s initial screening. Qualified candidates have an ample ovarian reserve for both their own needs and sharing. Egg share donors also often work closely with a fertility doctor to determine, based on their own medical history, the optimal number of eggs needed for their own future family-building goals. Should it make sense for the donor, they may choose to pursue a second egg-sharing cycle to maximize the chances of success for everyone.

Matching with a donor in our frozen program can provide the opportunity to move forward with your family-building plans faster, as frozen eggs can be fertilized or shipped to your clinic immediately. Donors undergoing frozen cycles complete equally rigorous ovarian reserve testing. While the total number of frozen eggs available will vary based on the donor’s retrieval outcomes, every frozen match is guaranteed to have a minimum of at least 6 frozen eggs.

To learn more about these programs and the differences between them, click here.

Birth rates with donor eggs vs patient eggs

The chart was made using the SART Patient Predictor for an average woman (5’4”, 150 lbs) with diminished ovarian reserve. As you can see, the chances of live birth after one donor egg cycle is 54% for recipients under 40, and only goes down slightly after this.

Find an amazing egg donor at Cofertility

At Cofertility, our program is unique. After meeting with hundreds of intended parents, egg donors, and donor-conceived people, we decided on an egg donation model that we think best serves everyone involved: egg sharing

Here’s how it works: our unique model empowers women to take control of their own reproductive health while giving you the gift of a lifetime. Our donors aren’t doing it for cash – they keep half the eggs retrieved for their own future use, and donate half to your family.

We are obsessed with improving the family-building journey — today or in the future — and are in an endless pursuit to make these experiences more positive. Create a free account to get started today!

Table of contents
Egg donation pricing

A human-centered egg donation experience

find your match
Copy
Halle Tecco
Halle Tecco, MPH, MBA
Halle Tecco is the Chair and Co-Founder of Cofertility, as well as a healthcare founder, investor, and women’s health advocate. She previously founded Rock Health and Natalist (acquired by Everly Health) and is an Adjunct Professor at Columbia Business School. Halle holds an MBA from Harvard Business School and an MPH from Johns Hopkins University.
Read more from Halle Tecco, MPH, MBA

Related articles

Woman holding compass in nature.
Infertility

Can Someone Please Explain Unexplained Infertility?

Sometimes, no explanation is the most frustrating explanation of all. We’re here to help explain…

Colorful pills scattered on white table.
Infertility

What’s the Deal With Clomid (For Real)?

How does Clomid work? Read on for everything you need to know about Clomid—side effects,…

Syringes sticking out of a red apple.
Infertility

What Are Some of the Most Common Fertility Drugs for Women?

An overview of some of the most common fertility drugs for women, when they’re prescribed,…

an abstract painting with orange

POI, POF, POR, DOR, FOR, TOR, Oh My! A Guide to Ovarian Reserve Acronyms

About

Decoding the mysteries of infertility can sometimes feel like navigating a maze of medical jargon — POI, POF, POR, DOR, FOR… it can be enough to make your head spin. The journey is often filled with complex terminologies and a multitude of acronyms like these, making the process feel even more overwhelming than it already is. 

Each of these acronyms represents a distinct condition or factor that can influence fertility, and understanding them is vital to making informed decisions about your reproductive health.

These acronyms pertain to various ovarian conditions that can contribute to infertility, each with their unique challenges and treatment considerations. Though these conditions can introduce obstacles on the journey to parenthood, modern advancements in reproductive medicine provide promising solutions. In particular, egg donation stands as a beacon of hope for many individuals and couples navigating these challenges.

This article is designed to guide you through the intricacies of these terms, what they signify, their implications, prevalence, and treatment options. Whether you’re just starting your journey or are already deep into exploring infertility treatments, understanding these terms can empower you to make informed decisions about your reproductive health.

POI – Premature Ovarian Insufficiency

What is Premature Ovarian Insufficiency

Premature Ovarian Insufficiency, or POI, is a condition where a woman’s ovaries stop functioning normally before she reaches 40. This results in decreased fertility due to a lower production of eggs, irregular periods or even cessation of menstrual cycles. 

What causes Premature Ovarian Insufficiency

The causes can be varied, from genetic disorders to autoimmune diseases, and even certain treatments like chemotherapy. In cases of POI, the option of using donor eggs is a viable solution, as it bypasses the issue of egg production, providing a chance at successful conception.

Prevalence of Premature Ovarian Insufficiency

POI affects approximately 1% of the general population

How Premature Ovarian Insufficiency is treated

There is no cure for POI, but there are several treatment options available. Hormone replacement therapy (HRT) can help alleviate symptoms of menopause and reduce the risk of osteoporosis and heart disease. Those with POI who wish to conceive can also explore fertility treatments like in vitro fertilization (IVF) with donor eggs. Not only can this option (of course) assist with egg quantity, but donor eggs also come from women who are likely to have higher quality eggs and produce healthy embryos.

POI – Primary Ovarian Insufficiency

Primary Ovarian Insufficiency means the same thing as Premature Ovarian Insufficiency: when the ovaries stop functioning normally before age 40. When talking about POI, “Primary Ovarian Insufficiency” is the preferred acronym over “Premature Ovarian Insufficiency” by the National Institutes of Health, because ovarian function is unpredictable in many cases. Also, since 5–10% of women with POI experience unassisted pregnancy, POI is different from menopause, when unassisted pregnancy is impossible. 

POF – Premature Ovarian Failure

Premature Ovarian Failure (POF), also often used interchangeably with POI, is a condition where the ovaries cease to function before the age of 40. In 2016, the New European Society of Human Reproduction and Embryology (ESHRE) proposed using the term “premature ovarian insufficiency” instead for research and clinical practice. 

POR – Poor Ovarian Response

What is Poor Ovarian Response

Poor Ovarian Response is a condition characterized by an inadequate response to ovarian stimulation during assisted reproductive procedures, such as In-Vitro Fertilization (IVF). Those with POR produce fewer eggs even when given fertility drugs designed to stimulate egg production. This condition reduces the chances of successful IVF due to the lower number of eggs available for retrieval and fertilization. 

Prevalence of Poor Ovarian Response

The estimated prevalence of POR ranges from 6% to 35%. This wide range is primarily due to researchers and clinicians having varying definitions of POR. 

How Poor Ovarian Response is treated

Different strategies are employed to manage POR, such as using different protocols or higher doses of fertility drugs. There is some evidence that DHEA and CoQ10 may improve IVF pregnancy rates for those facing POR as well as some evidence that treatment with growth hormone (GH) for POR patients could lead to a higher number of retrieved eggs. In certain cases, fertility doctors may recommend alternative approaches such as the use of donor eggs or embryo adoption. These options can increase the chances of success by (ideally) giving you more healthy embryos to work with over a shorter period of time.

DOR – Diminished Ovarian Reserve

What is Diminished Ovarian Reserve

Diminished Ovarian Reserve refers to a decrease in the quantity of eggs. This condition is often related to aging, as the number of eggs declines naturally over time, but it can also occur prematurely in some. 

Prevalence of Diminished Ovarian Reserve

Between 10% to 30% of people who seek help for infertility have DOR.

How Diminished Ovarian Reserve is treated

Fertility treatments like IVF may be employed, but success rates can be lower due to fewer eggs. Depending on your family-building goals and timeline, the use of donor eggs from a younger, healthy donor can improve embryo fertilization outcomes by providing more eggs, in addition to significantly increasing the likelihood of pregnancy and reducing the risk of miscarriage.

FOR – Functional Ovarian Reserve

What is Functional Ovarian Reserve

Functional Ovarian Reserve refers to the number of responsive follicles in the ovaries at a given time. It is frequently used synonymously with the term ‘ovarian reserve’. Several research groups have used markers such as hormone levels or Antral Follicle Count (AFC) of follicles with diameters between 2-10 mm to measure FOR. Therefore, it seems that FOR is the term used to represent a biological quantification of the ovarian reserve. It is different from the diagnosis of Diminished Ovarian Reserve (DOR), which is based on a low Antral Follicle Count and/or hormonal indicators of reduced ovarian reserve.

Total Ovarian Reserve (TOR):

What is Total Ovarian Reserve

The Total Ovarian Reserve refers to the total number of immature eggs (primordial follicles) in the ovaries. This reserve is established at birth, decreases naturally with age, and can be influenced by certain medical conditions or treatments. 

Prevalence of Total Ovarian Reserve

A decline in TOR is a normal part of aging. However, some patients may experience a faster-than-normal decline due to conditions like POI or POF.

How Total Ovarian Reserve is treated

There is currently no proven method to increase the TOR since the number of eggs is established before birth. Fertility treatments aim to make the best use of the existing reserve and include ovulation induction, in-vitro fertilization (IVF), and in many cases, the use of donor eggs. Donor eggs provide a significant benefit for those with a low TOR, offering more eggs— and because they come from young, healthy donors, they increase the chance of a successful pregnancy. 

Create a free account to find your perfect egg donor today

What do these acronyms have in common? The “O.”

The unifying thread that weaves these acronyms together is the letter “O,” representing “Ovarian.” This commonality underlines the critical role the ovaries play in the reproductive system. Ovaries are responsible for egg production, crucial for the conception and reproduction process. Any disruption or disorder affecting the ovaries can have significant impacts on a woman’s fertility.

Ovarian function

In conditions like POI and POF, the issue arises from an early cessation or significant decrease in ovarian function. The ovaries prematurely reduce their activity, leading to a limited supply or a complete lack of viable eggs.

Ovarian response

With POR, the ovaries do not respond adequately to fertility treatments designed to stimulate egg production. This poor response leads to fewer eggs being produced than expected, reducing the success rates of assisted reproductive techniques such as IVF.

Ovarian reserve

DOR, TOR, and FOR are all about the ‘reserve’ of eggs in the ovaries. They refer to the quantity of the eggs a woman has left. DOR is a decrease in the amount or quality of the eggs, TOR refers to the total number of immature eggs (primordial follicles) in the ovaries, and FOR refers to the number of responsive follicles or eggs that can potentially be fertilized.

These acronyms all point to various challenges related to the ovaries that can influence fertility. Understanding these terms allows for more informed discussions with healthcare professionals about potential treatment strategies.

What is the success rate of donor egg IVF?

Donor egg IVF has the highest success rate of any fertility treatment, and using donor eggs can drastically increase your chances of success. 

At every age, the chances of birth with donor eggs is better, but those who benefit the most from donor eggs are women over 35 and those with low ovarian reserve. In fact, about one-quarter of women over 40 who succeeded with IVF did so through the use of donor eggs. 

At Cofertility, for those who match with a donor in our fresh egg donation program, the average number of mature eggs a family receives and fertilizes is 12. The number of eggs retrieved varies by patient and cycle, but can be predicted by a donor’s age, AMH, and antral follicle count, all of which will be known to you after the donor’s initial screening. Qualified candidates have an ample ovarian reserve for both their own needs and sharing. Egg share donors also often work closely with a fertility doctor to determine, based on their own medical history, the optimal number of eggs needed for their own future family-building goals. Should it make sense for the donor, they may choose to pursue a second egg-sharing cycle to maximize the chances of success for everyone.

Matching with a donor in our frozen program can provide the opportunity to move forward with your family-building plans faster, as frozen eggs can be fertilized or shipped to your clinic immediately. Donors undergoing frozen cycles complete equally rigorous ovarian reserve testing. While the total number of frozen eggs available will vary based on the donor’s retrieval outcomes, every frozen match is guaranteed to have a minimum of at least 6 frozen eggs.

To learn more about these programs and the differences between them, click here.

Birth rates with donor eggs vs patient eggs

The chart was made using the SART Patient Predictor for an average woman (5’4”, 150 lbs) with diminished ovarian reserve. As you can see, the chances of live birth after one donor egg cycle is 54% for recipients under 40, and only goes down slightly after this.

Find an amazing egg donor at Cofertility

At Cofertility, our program is unique. After meeting with hundreds of intended parents, egg donors, and donor-conceived people, we decided on an egg donation model that we think best serves everyone involved: egg sharing

Here’s how it works: our unique model empowers women to take control of their own reproductive health while giving you the gift of a lifetime. Our donors aren’t doing it for cash – they keep half the eggs retrieved for their own future use, and donate half to your family.

We are obsessed with improving the family-building journey — today or in the future — and are in an endless pursuit to make these experiences more positive. Create a free account to get started today!