Did you know that women get a lifetime supply of eggs at birth?
In fact, a baby girl is born with all of the eggs that she will ever have, roughly 1-2 million total. Even though it will be many years – even decades – before a select few are called to duty and go through the steps of maturation and ovulation, the overall supply slowly declines over time. At puberty there are roughly 400,000 eggs in the ovaries; by menopause this number is less than 1,000. Over an entire reproductive lifespan, only about 400 eggs will ultimately get ovulated. Thus the odds for any given egg to result in a successful pregnancy are remarkably slim.
Reproductive aging occurs for all women and results in the slow loss of the egg supply over time. Although the average age of menopause is 51 years, the age where most women become infertile begins nearly 10 years before the final menstrual period. The lower end for normal menopause is 40 years, meaning that some women can experience a sharp decline in their fertility potential even in their 20s or 30s.
Decreasing egg quantity also comes with decreasing egg quality, which may result in infertility or miscarriage. Once the egg supply is permanently depleted, there is no way to create new eggs. Assessing the potential egg supply – both quantity and quality – is a critical early step in fertility testing. “Ovarian reserve” is a term used to describe the robustness of the egg supply. Although there is currently no method to count the exact number of eggs in the ovaries, a combination of hormonal blood tests and ultrasound findings help create an overall picture of the egg supply and give an estimate of fertility potential.
One of the many frustrations that we, as infertility specialists, hear from patients is that they wished they would have known their eggs numbers were lower than expected earlier in order to have higher success with fertility treatments. With egg freezing becoming more reliable many women are turning toward this avenue to “stop their biological clock,” especially if they wish to delay having children.
Our clinic offers consultations with infertility specialists to discuss ovarian reserve testing and possible egg freezing. Please call the office for more details (651) 222-6050.