13th September 2013 | by MFC Team
I am 33 and not in a position to have children for at least another 5 or 6 years. I’ve been freaking out with all the talk these days about age-related fertility declines. But I recently read an article by Jean Twenge that argues fertility doesn’t drop off the map for women in their mid- to late 30s. Is it true that the majority of women can safely wait to have children until their late 30s and early 40s? I guess what I’m really asking is “how long I can wait”?
Written by our medical expert Dr. Beth Taylor, co-founder and co-director of Olive Fertility Centre, Vancouver, British Columbia.
As women, we’re born with a certain number of eggs, and each month, in fact almost every day, eggs are being used or dying. Eventually we run out of eggs and that’s when the menopause occurs.
The rate at which we lose eggs is not in our control, unfortunately. While some lifestyle choices can slightly change the rate of egg loss (e.g. cigarette smoking causes eggs to be lost faster), genetics matter the most. As egg number declines, so does egg quality. Lower quality eggs are harder for sperm to fertilize and are less likely to make healthy embryos that will attach and grow in the uterus. As a result, fertility declines with age.
How fast does fertility decline?
Jean Twenge’s article is quite accurate in that there is not a sudden decline in fertility in the mid-thirties. There is actually a slow decline from the early twenties and by the mid-thirties the rate of decline increases. What this means is that many women will be able to conceive on their own into their late thirties, but more and more women each year will not be able to do so. To put it into numbers by total pregnancy rate after one year of trying, at age twenty 95% of couples can conceive on their own, at thirty 90% can, at thirty-five 80% can, at forty 60% can, at forty-five 10% can and by 50 essentially no one can.*
Conceiving does not mean a healthy pregnancy and baby, though. At age forty 30% of pregnancies end in miscarriage and by forty-five that rises to 60%. Further, at forty 1 in 100 babies will have Down Syndrome which rises to 1 in 20 by age forty-five.
The problem is that it is very difficult to know if you will be in the fertile group or the infertile group. If only we had a crystal ball to know how long you would be fertile! Since we don’t, it’s safest to conceive when the numbers for pregnancy, miscarriage and health are stacked in your favor. If the circumstances of your life prohibit you from having children when you are younger, then egg freezing is now a viable option, particularly for women under the age of 38.
What can you do?
Knowing if the women in your family had infertility and when they went through the menopause is helpful. Additionally, knowing your egg count (ovarian reserve) can also help – if your egg numbers are good then you are likely fertile for months to years. Your doctor can help you assess your ovarian reserve which is done with a simple blood test.
*NOTE: This is not the same as per cycle pregnancy rates, which are lower for all age groups. See the per cycle pregnancy rates by age by clicking here.