What Is Diminished Ovarian Reserve?
Quick Answer
Diminished ovarian reserve (DOR) is a condition where a woman has fewer eggs in her ovaries than expected for her age. It affects an estimated 10 to 30% of women seeking fertility treatment and is one of the most common reasons for difficulty conceiving. DOR does not mean pregnancy is impossible, but it often requires earlier intervention and personalized treatment.
Markham Fertility Centre offers comprehensive ovarian reserve testing and individualized treatment plans for patients with DOR across five Ontario locations.
How Ovarian Reserve Works
Women are born with all the eggs they will ever have. This fixed supply, called the ovarian reserve, decreases naturally over time:
| Life stage | Approximate egg count |
| Birth | 1 to 2 million |
| Puberty | 300,000 to 400,000 |
| Age 30 | ~100,000 |
| Age 37 to 38 | ~25,000 (accelerated decline begins) |
| Age 40 | ~25,000 or fewer |
| Menopause | ~1,000 |
Ovarian reserve reflects both the quantity and quality of remaining eggs. As egg count drops, egg quality also tends to decline, increasing the risk of failed fertilization, implantation failure, and miscarriage.
Causes of Diminished Ovarian Reserve
Age is the strongest predictor, but DOR can affect younger women as well. Common causes include:
- Natural aging: Egg loss accelerates after 35 and becomes rapid after 37 to 38
- Genetic factors: Family history of early menopause, chromosomal abnormalities (such as Fragile X premutation or Turner syndrome)
- Ovarian surgery: Removal of ovarian cysts, endometriomas, or tissue from prior procedures
- Endometriosis: Can damage ovarian tissue and reduce follicle count
- Cancer treatment: Chemotherapy and pelvic radiation can destroy eggs
- Autoimmune conditions: Some autoimmune disorders affect ovarian function
- Smoking: Accelerates egg loss and reduces egg quality
- Idiopathic (unknown): In many cases, no specific cause is identified
Symptoms
Most women with diminished ovarian reserve have no obvious symptoms. The condition is typically discovered through fertility testing after difficulty conceiving. Some women may notice:
- Shorter menstrual cycles (for example, a 28-day cycle becoming 24 to 25 days)
- Difficulty conceiving after 6 to 12 months of trying
- In more advanced cases, early menopausal symptoms such as hot flashes, irregular periods, or vaginal dryness
Because DOR is often silent, proactive ovarian reserve testing is valuable for women who want to understand their fertility potential before actively trying to conceive.
How Diminished Ovarian Reserve Is Diagnosed
Diagnosis involves a combination of blood tests and imaging, typically performed on day 2 or 3 of the menstrual cycle:
| Test | What it measures | DOR indicators |
| AMH (anti-Mullerian hormone) | Number of remaining follicles | Below 1.0 ng/mL suggests DOR; undetectable levels indicate severe DOR |
| FSH (follicle-stimulating hormone) | How hard the body is working to stimulate the ovaries | Above 10 mIU/mL is mildly elevated; above 15 mIU/mL indicates poor response to stimulation |
| Estradiol (E2) | Baseline estrogen level; helps interpret FSH | Elevated early estradiol (above 80 pg/mL on day 3) can mask a high FSH |
| Antral follicle count (AFC) | Number of small follicles visible on ultrasound | Fewer than 5 to 7 follicles on both ovaries combined suggests DOR |
AMH and AFC are considered the most reliable markers. Your fertility specialist may use a combination of all four to get a complete picture.
At Markham Fertility Centre, ovarian reserve testing is part of every initial fertility assessment, and the on-site genetics program can screen for conditions like Fragile X that contribute to early ovarian decline.
Treatment Options
There is no treatment to reverse diminished ovarian reserve or restore egg count. However, several strategies can help patients with DOR achieve pregnancy:
Fertility preservation (egg or embryo freezing):
- Recommended as an immediate step for women diagnosed with DOR who are not yet ready to conceive
- Freezing eggs while quality is still viable preserves future options
- The earlier this is done, the better the outcomes
IVF with personalized stimulation protocols:
- Higher or adjusted medication doses may help retrieve a few viable eggs
- Mini-IVF or natural cycle IVF may be appropriate for patients who respond poorly to standard stimulation
- Success rates are lower than for women with normal reserve, but pregnancy is achievable
IVF with donor eggs:
- Often the most effective option for patients with severely diminished reserve or very poor egg quality
- Donor eggs come from younger, screened donors, significantly improving success rates
- At Markham Fertility Centre, the Health Canada-approved Donor and Surrogacy program supports the full donor egg process
IUI with ovulation induction:
- May be an option for mild DOR when fallopian tubes are open and sperm quality is adequate
- Lower success rates than IVF, but less invasive and less expensive
Lifestyle adjustments:
- Quitting smoking, maintaining a healthy weight, and reducing toxin exposure support overall egg quality
- These measures cannot restore egg count but may improve outcomes during treatment
DOR and Age: What the Numbers Mean
| Age group | Typical AMH (ng/mL) | Expected AFC | IVF success rate |
| Under 30 | 2.0 to 4.0+ | 15 to 30 | 40 to 50% |
| 30 to 35 | 1.5 to 3.0 | 10 to 20 | 35 to 45% |
| 35 to 38 | 1.0 to 2.0 | 5 to 15 | 25 to 35% |
| 38 to 40 | 0.5 to 1.5 | 3 to 10 | 15 to 25% |
| Over 40 | Below 1.0 | Below 5 | 5 to 15% |
These are general benchmarks. Individual outcomes vary based on egg quality, sperm quality, and treatment approach.
Why Patients in Ontario Choose Markham Fertility Centre for DOR
- Comprehensive ovarian reserve testing (AMH, FSH, estradiol, AFC) as part of every initial assessment
- Personalized IVF protocols tailored to low ovarian reserve, including modified natural cycle and mini-IVF options
- On-site genetics program for Fragile X screening and PGT counselling
- Pain-free egg retrieval with an anesthesiologist at every procedure
- Health Canada-approved Donor and Surrogacy program for patients who need donor eggs
- Five locations across Markham, Barrie-Innisfil, Oshawa, Orillia, and Sudbury
Book a fertility assessment at Markham Fertility Centre →
FAQ
Can I still get pregnant with diminished ovarian reserve?
Yes. DOR reduces your chances but does not eliminate them. You only need one healthy egg to achieve pregnancy. Treatment options include IVF with tailored stimulation protocols and, in more severe cases, IVF with donor eggs.
At what age should I get my ovarian reserve tested?
Any woman concerned about her fertility timeline can request testing. It is especially recommended if you are over 35, have a family history of early menopause, have had ovarian surgery, or have undergone cancer treatment. In Ontario, most diagnostic fertility testing is covered by OHIP.
Is low AMH the same as infertility?
No. A low AMH indicates fewer remaining eggs but does not measure egg quality. Some women with low AMH conceive naturally or with treatment. AMH is best interpreted alongside FSH, estradiol, and antral follicle count for a complete picture.
Can lifestyle changes improve diminished ovarian reserve?
Lifestyle changes cannot increase your egg count, but quitting smoking, maintaining a healthy weight, and reducing stress may support egg quality and improve treatment outcomes.