A Brief History of Egg Freezing
Attempts at freezing eggs, sperm, and embryos have been going on for decades. While freezing sperm and embryos has been successful for some time, early methods of egg freezing were fraught with difficulties and had very poor success rates. Briefly … when eggs were cooled to freezing temperatures, they developed ice crystals within the cell, which made proper fertilization and development (to become a baby) less successful. What revolutionized egg freezing was the discovery that if eggs were cooled very rapidly (vitrification), ice crystals did not form and the eggs were well preserved. Initially performed in the 1980s, vitrification of eggs is now standard practice in advanced fertility centers.
How Good are Frozen Eggs?
The majority of eggs frozen in recent years remain untested, sitting in storage tanks awaiting the next step. We never know which eggs and how many of them will become a baby years down the road. However, study after study has shown that pregnancy rates using frozen eggs are similar to pregnancy rates using in-vitro fertilization with fresh eggs. This is the key – future pregnancy rates with frozen eggs are as good as if a woman did an IVF cycle at the time of egg freezing. This varies from patient to patient depending on age, ovarian reserve (please see my blog on AMH), pregnancy history and overall health. As most patient’s wanting to freeze eggs do not have a diagnosis of infertility, they likely have a higher proportion of normal eggs fully capable of becoming a baby.
How Many Eggs Should I Freeze?
This is truly a personal decision, depending on a patient’s age and overall family plan (and willingness to see me on a daily basis!). I typically recommend freezing approximately 10-15 mature eggs, as this number provides the reasonable insurance policy that most patients are comfortable with. Fortunately, this can often be accomplished in one month’s stimulation cycle. However, many patients desire more eggs for greater insurance, and thus need multiple cycles.
Egg freezing is an amazing technology that can help my patients preserve their fertility. Whether or not they ultimately need to use their frozen eggs, having eggs frozen gives my patients more options … and having more options is a good thing!