All infertility patients have heard the mantra at one point: “We only need one good egg”. Dr. Tortoriello of Sher Fertility Institute New York is an expert when it comes to Diminished Ovarian Reserve (DOR) and in his blog below he talks about this fertility issue in length.
It is indeed true that the rate-limiting step to achieving success in most infertility treatment journeys is the acquisition of a healthy, or chromosomally normal, oocyte. Each oocyte during its maturational process must discard half of its chromosomal content, going from 46 chromosomes (“diploid”) to 23 chromosomes (“haploid). The key processes involved in this transformation occur very late in the lifespan of the egg, essentially within a 36-hour time span following the mid-cycle surge of LH in natural cycles or the hCG “trigger” shot in IVF cycles. Unfortunately, the lattice-like structures that attach and align the chromosomes in each oocyte become faulty and fragile as a woman ages, and this leads to the release of mature eggs with abnormal numbers of chromosomes. These eggs will yield poor outcomes, either no pregnancy or a pregnancy that ends with miscarriage. Given the role of aging upon egg DNA stability, it is no surprise that younger women are able to more frequently produce normal eggs. Therefore younger women in their twenties to mid-thirties, are more likely to conceive with any fertility treatment even if their egg reserve is considerably lower than their age would suggest.
Prematurely low egg reserve, therefore, does not apparently equate to prematurely poor egg quality. In general, we know this to be true because younger DOR patients do much better than older DOR patients across all fertility treatments. But if the reason for DOR stems from ovarian injury of some sort, such as from cancer treatments (chemotherapy or radiation), one should expect a decrease in both regardless of age. There is also some evidence that the inflammation from endometriosis can exert a similar, although much milder effect. In these patients, one must weigh the invasivity of surgery to remove endometriosis against a small benefit in egg quality.
I recall a patient in her twenties who was referred to me for greatly diminished ovarian reserve with over a year of infertility. Her cycles were irregular and her serum markers for egg reserve were in the menopausal range. At our first visit, I did a sonogram and saw a single large follicle on one ovary. Her hormone levels showed high estrogen levels, suggesting that this was a genuine follicle. That same day I asked her to take an hCG trigger shot and have well-timed intercourse with her partner. She conceived and now has a son. Obviously her egg that day was a good one! Unfortunately, women older than she would have been much less likely to get the same result. In a future blog, I shall delve more into understanding and treating older women with DOR as they require a more persistent and nuanced approach.