If you have ovaries and are experiencing infertility, you may receive a diagnosis of diminished ovarian reserve. Here’s what that means.
The ovaries contain all the follicles they will have for that person’s lifetime. This is called our “ovarian primordial follicular pool.” It refers to the number of premature eggs remaining in our baskets. Every cycle the ovaries (with the help of hormones) recruit a small group of these follicles to step up and try to grow. In a natural cycle, only one egg will be allowed to mature out of that small group, while the remaining participants die off. So, with each passing cycle, women slowly deplete their egg reserves. Diminished ovarian reserve (DOR) simply means that there are less follicles available in the ovaries to try to recruit. It’s important to note that a lower egg quantity doesn’t necessarily mean there is lower egg quality. Although it’s an important variable to consider in your fertility journey, it shouldn’t be misinterpreted as the inability to conceive.
What causes diminished ovarian reserve?
Diminished ovarian reserve is most commonly due to aging, but, from a biological perspective, not everyone ages at the same rate. This means that not all 40-year-olds have a diminished reserve, but all of them have a lower reserve than they did 10 years ago. There’s also the possibility of having a low egg reserve earlier than expected. When there is essentially no more reserve, and the ovaries stop functioning this is menopause. If this occurs earlier than expected (typically understood as before the age of 40), it's premature ovarian failure or premature ovarian insufficiency, which occurs in about one percent of women and can be due to genetic factors, autoimmune conditions or previous damage to the ovaries (often due to surgery, chemotherapy or radiation treatment). Smoking cigarettes can also cause women to go through early menopause, and it is considered the most important modifiable risk factor if you wish to be proactive.
How do you know if you have diminished ovarian reserve?
In cases of DOR, some women might notice their periods don’t come as often or stop showing up altogether. But for others, there might not be any signs or symptoms until you’ve been trying to conceive unsuccessfully and have a full workup done with a fertility clinic.
There are two main tests that best estimate ovarian reserve:
- Anti-Mullerian hormone (AMH): This hormone is made and released by the recruited follicles and can be measured by a blood test. A low AMH indicates lower ovarian reserve (low number of follicles recruited and available) and in general AMH decrease as we age.
- Antral follicle count (AFC): This is determined by a transvaginal ultrasound that counts the number of follicles recruited to grow that cycle. This is traditionally done day two to five of the menstrual cycle to get the most accurate results. A low AFC indicates that less follicles are being called up—a sign that there are not as many left in the pool.
What is the typical treatment for those with DOR who want to conceive?
If you have a low ovarian reserve and want to conceive, you could conceive without intervention, as it’s not considered a measure of egg quality. On any given cycle if a high-quality viable egg comes along and all other factors are reassuring, then it might just do the trick. That said, having diminished ovarian reserve impacts your timelines and chances of success even with treatments like IVF, so it’s always best to be proactive and get assessed by a fertility clinic to review your specific treatment options.
The most common initial fertility treatment with DOR is controlled ovarian hyperstimulation (COH). Essentially, we want to stimulate the ovaries with hormonal treatments to to help the eggs develop and mature, and recruit more eggs per cycle. If your partner’s sperm quality is adequate and having sex isn’t an issue for you, then the COH will be synced with timed intercourse and a trigger shot to initiate ovulation. If sperm quality is an issue, your doctor may suggest also pairing COH with intrauterine insemination (IUI), where a washed sperm sample is inserted directly into the uterus using a catheter.
To optimize egg quantity and ensure all eggs have the best chance to fertilize, your doctor may suggest IVF. In IVF, ovaries are stimulated to produce multiple mature eggs. These can be retrieved, fertilized or injected with a sperm cell, and then we wait and see over the next five days if we have a healthy embryo that can then be transferred into your uterus.
If your ovaries don’t respond to hormone medications your chances of success with IVF are minimal. You may be counselled on the possibility of needing to use donor eggs or donor embryos if you wish to carry the pregnancy yourself.