Many patients come to me in their late 30s and 40s to either assess their relative fertility or to start fertility treatments, and they are often unpleasantly surprised to find out that their ovarian reserve is low. It might be age-appropriate or even lower than age might predicate, but both scenarios are frequently met with consternation.

We know that there are several things that can hasten ovarian follicular demise and lower the egg count prematurely.  Among these factors include a history of smoking, heavy alcohol consumption, chemotherapy or radiation, ovarian surgery, and possibly ovarian endometriosis (endometrioma cysts). Time, as well as all of these insults, chips away at a woman’s egg reserve until her ovaries are depleted of oocytes by ~ age 50.  Unfortunately, no matter how healthy a lifestyle the woman practices, her ovaries will follow their own pre-programmed calendar of oocyte attrition.  There is nothing one can do, to the best of our knowledge, that will slow follicular loss, let alone help to generate new follicles.

Some hope that new oocytes/follicles could be generated came in 2004 from the research being conducted by the laboratory of Dr. Jonathan Tilly, whose work at Massachusetts General Hospital was met with rapt attention when he presented data suggesting that the ovaries contained oocyte stem cells (1). It was believed that if these cells could be triggered to mature either in vivo or in vitro that new oocytes could be provided for women with low to no egg reserve.  Unfortunately, that data has now come under intense scrutiny and the cells previously identified as ovarian stem cells may be in fact perivascular cells, which support blood vessel structure and help regulate blood flow (2).

At this time, the only way to halt the biological clock is the freezing of a woman’s oocytes to keep them in a form of “suspended animation” for her future use.  Thankfully this technique has been perfected.  It entails essentially performing the IVF process up until the point of egg retrieval. The retrieved eggs are not fertilized but rather rapidly frozen in a technique called “vitrification” in which the aqueous contents of the oocyte are not given an opportunity to form ice crystals, and by avoiding this, the future health of the egg upon being thawed is greatly maximized. In fact, at Sher Fertility Solutions, our oocyte survival rate upon thaw is now ~ 95%, just a tiny bit less than that of our blastocyst embryo thaw survival rate of 97%. Given this technique has been made standard and highly efficient, oocyte vitrification is an excellent option for women seeking to be proactive about their future fertility.  We have also taken to utilizing an artificial intelligence program called “Violet”, created by the team at Future Fertility, that can scrutinize high-resolution photomicrographs of oocytes and determine how likely each oocyte is to fertilize and become a healthy-appearing day 5 or 6 blastocyst embryo when it is ultimately thawed and introduced to sperm.  The oocyte vitrification process is a superb method for fertility preservation and hopefully will grow to become more well-known and more widely available to those who could truly benefit from it.


  1. Johnson, J., Canning, J., Kaneko, T. et al. Germline stem cells and follicular renewal in the postnatal mammalian ovary. Nature 428, 145–150 (2004).
  2. Wagner, M., Yoshihara, M., Douagi, I. et al. Single-cell analysis of human ovarian cortex identifies distinct cell populations but no oogonial stem cells. Nat Commun 11, 1147 (2020).