Is Age Just a Number When It Comes to Fertility?
When it comes to egg freezing, timing can be everything. You want to make sure you’re mentally and financially prepared, you have a few weeks of downtime from obligations outside of normal daily life, and you’re generally healthy and taking care of yourself. On top of that is the not-so-small issue of age and its impact on fertility. Younger women typically have more eggs, healthier eggs, and are able to retrieve a higher number of eggs during a single egg freezing cycle, which is why most OB/GYNs recommend freezing eggs before age 35. That said, if you’re over 35 and interested in freezing your eggs, the best thing you can do is schedule fertility testing with a reputable reproductive endocrinologist to get the ball rolling today.
To help you understand the best age to freeze eggs, let’s go back to Fertility 101 for some basics on female reproduction. An egg is a single cell that’s made mostly of water and contains half the DNA needed to create a fetus! Female egg production happens in the womb – your mother’s womb, that is. We’re born with roughly one to two million eggs, and these are all of the eggs we’ll have during our lifetimes. As we get older the number of eggs in our ovaries declines at a steady pace up until our early 30’s, and even before we get our first period nearly half of the eggs we started with have naturally died. By the time we’re in our peak reproductive years, between about 18-26 years old, we have about 20-40% of our eggs left, and at age 30 we’re left with only 10-12% of the eggs we started with.
As if that’s not bad enough, by the time we’re 40 our eggs are down to about 3-5% of that original number. Add to that the fact that egg quality also declines as we get older since our eggs age with us. Older eggs are more likely than younger ones to have genetic and chromosomal abnormalities that could prevent them from forming healthy embryos. It makes sense that women over 35 typically need more than one egg freezing cycle to retrieve the recommended 15-20 eggs that a younger women may get on their first try. Per frozen egg, there’s about a 5% chance of a live pregnancy when you’re ready to thaw and use your eggs down the line. However, that number increases a few points for younger eggs that are typically higher in quality, and may decrease a point or two for older eggs that are at a higher risk for abnormalities. Since we know it’s the age of the eggs rather than the womb that predicts pregnancy success rates, you should think about freezing your eggs sooner rather than later even if you don’t plan on using them for five to ten years.
So when is the best age to start your fertility preservation? Experts agree that women who know they want to delay motherhood should aim to freeze their eggs by 35, and the younger the better. Fertility takes its first bump at about age 32 with another big bump at 35, which is why we recommend being proactive about your future. This means having your AMH tested annually starting in your mid to late 20’s, discussing your personal fertility window with your doctor, and planning to freeze your eggs before fertility starts to decline. What is AMH, you ask? Anti-mullerian hormone, a hormone produced by growing follicles in our ovaries, which helps your doctor predict how many eggs you have left. More follicles, or sacs where eggs grow, mean more eggs are being prepped to ovulate during each menstrual cycle. In an egg freezing cycle, your doctor will prescribe the same hormones your body naturally produces in an effort to stimulate more follicles to complete maturing eggs at once. If you’re already growing multiple follicles naturally, it’s a good predictor that you’ll be able to retrieve more eggs during a cycle of egg freezing. AMH only tells you how fertile you are right now, not whether you’ll still be fertile in a year or two. That’s why it’s recommended to test your fertility annually so you can stay on top of any changes.
In the end, the ideal age for you to freeze your eggs is as soon as you and your doctor are comfortably ready. If you can’t freeze your eggs now due to travel commitments, work or school, or cost, the most important thing you can do is be proactive about your fertility. Test your AMH annually, take care of yourself with proper nutrition, rest, and balanced exercise, and keep your OB/GYN up to date on any changes in your cycle. Women who stay on top of their fertility health give themselves a big leg-up on realizing their future family goals!