Infertility can present challenges for individuals and couples hoping to build a family. Diminished ovarian reserve (DOR) is a common concern, involving a reduced capacity of the ovaries that impacts a woman’s ability to conceive.
What is Diminished Ovarian Reserve?
Ovarian reserve refers to the quantity and quality of eggs remaining in a woman’s ovaries. Women are born with a finite number of eggs, which gradually decline throughout their reproductive years. Diminished ovarian reserve (DOR) signifies a lower-than-expected number of eggs for a woman’s age, often with reduced quality.
While a natural decline in ovarian reserve occurs with age, with fertility potential diminishing after age 30 and more rapidly after 40, DOR can manifest prematurely. Some women may experience this decline in their 20s.
At birth, a female typically has between one and two million eggs, a number that decreases to approximately 300,000 by puberty. By the late 30s, this number may further decline to around 27,000. The loss of eggs is a continuous process, occurring regardless of pregnancy or contraceptive use, and can be accelerated by factors such as smoking, certain medical treatments like chemotherapy or radiation, and genetic conditions.
Identifying Diminished Ovarian Reserve
Diminished ovarian reserve often presents without noticeable symptoms, with many women discovering the condition during fertility testing. However, some individuals might experience unexplained difficulty conceiving or notice consistently shorter menstrual cycles. These signs can prompt medical evaluation for DOR.
Diagnosis typically involves a combination of blood tests and imaging techniques. Blood tests measure hormone levels that provide insight into ovarian function. Anti-Müllerian Hormone (AMH) is an indicator, as it is produced by ovarian follicles and reflects the remaining egg supply; lower AMH levels are characteristic of DOR. Follicle-Stimulating Hormone (FSH) and Estradiol levels are assessed, usually on the second or third day of the menstrual cycle, with elevated FSH and lower Estradiol suggesting decreased ovarian reserve.
Alongside blood tests, a transvaginal ultrasound is used to perform an Antral Follicle Count (AFC). This imaging technique estimates the number of small follicles (2 to 10 mm in diameter) present in the ovaries, which correspond to the pool of eggs available for development in a given cycle. A low AFC, typically between 3 and 10, further supports a diagnosis of DOR. While these tests help estimate the remaining egg supply and predict response to fertility treatments, they do not definitively predict the ability to conceive naturally.
How DOR Affects Fertility
Diminished ovarian reserve impacts a woman’s ability to conceive by affecting both the quantity and quality of her eggs. A reduced egg count means fewer available eggs for fertilization each cycle, lowering the chances of conception. The decline in egg quantity correlates with a decrease in egg quality as women age.
Compromised egg quality involves a higher incidence of chromosomal abnormalities, which can lead to lower fertilization rates, reduced embryo development potential, and an increased risk of miscarriage. Even with assisted reproductive technologies, success rates can be lower for individuals with DOR compared to those with normal ovarian reserve. While ovarian reserve is a factor in fertility treatment outcomes, it may not directly influence the chance of natural conception, provided regular menstrual cycles are maintained.
Treatment Strategies for DOR
For individuals diagnosed with diminished ovarian reserve, treatment strategies aim to optimize the chances of conception. Assisted Reproductive Technologies (ART), particularly In Vitro Fertilization (IVF), are considered. In IVF cycles for women with DOR, higher dosages of fertility medications may be used to stimulate the ovaries, though increasing medication dosage beyond a certain point may not significantly improve outcomes. Specialized IVF protocols, such as the antagonist “short” protocol or the “flare” protocol, are employed to maximize the response from the limited egg supply.
Despite the challenges, IVF can be an option, and success rates vary depending on factors like age and the specific cause of DOR. Even with DOR, if eggs are retrieved, younger women may still have reasonable success rates. However, the cancellation rate for IVF cycles can be higher for women with DOR due to poor ovarian response.
When using a woman’s own eggs remains challenging or unsuccessful, egg donation is an effective option for those with severe DOR. This involves fertilizing eggs from a donor with sperm and transferring the resulting embryo. Egg donation yields high success rates, providing a pathway to pregnancy when other methods are not feasible. Fertility preservation, such as egg freezing, may be considered for younger women at risk of future DOR to preserve their fertility for later use.