Now that I’m 35, my biological clock skips every time I read fertility statistics.
It’s a fact: a woman’s chances of getting pregnant go down with age, and our mid-30s is when the numbers take the most obvious turn. Actually, we start a slow fertility decline in our 20s, and it gains momentum into our 40s, when the outlook is the least rosy. Studies suggest that a healthy 30-year-old woman trying for a baby has about a 20 percent chance of getting pregnant each month. At 40, that number shrinks to 5 percent (though if she tries for an entire year, her chance is better than 40 percent.)
Add to it that the rate of miscarriage is higher in our 30s, as is the chance of having a baby with a genetic abnormality. A baby of a mom at age 25 has a 1 in 1,300 chance of having Downs syndrome (caused by faulty cell division that leaves baby with three instead of two copies of chromosome number 21). At 30, the chances are 1 in 1,000; at 35 its 1 in 400; and at 45, 1 in 35.
One of the reasons for the fertility decline is that, with time, the ovaries become less sensitive to the hormonal signals from our brain coaxing them to release an egg. Meanwhile, since we have a finite number of eggs, they naturally fall into shorter supply as the years go on. A baby girl is born with over a million eggs. By puberty around 300,000 of them are left, and from this bank, only around 300 will mature and release through ovulation. With age comes a higher likelihood of genetic hiccups as the eggs undergo early-stage cell divisions both before and after meeting sperm.
We certainly can’t ignore the numbers, and I’ve talked to fertility doctors who rue the phenomenon of late-blooming celebrity moms because they send the wrong message about fertility. The inevitable fact is that it’s harder and riskier the older we get.
But on the other hand, we have a habit of going off the rails a bit when it comes to health information. Part of the post-35 baby anxiety comes from our tendency to personalize health statistics; we see numbers and averages that were derived from data on millions of women and we take it as if it were a description of our own bodies.
The reality is that 35 is not a magic number. Your personal biology is unique, and it has an individual plan laid out for you. For good or ill, this could swing either way; perhaps your ovaries dropped in sensitivity in your late 20s, but they also may be programmed to keep right on track until your 40s.
In fact, one in five women in the U.S. has her first child after the age of 35 (not to mention the countless others who have a second or subsequent after their 35th birthday) and most are healthy moms with healthy babies. You probably know some of them yourself: friends or family members in early mid-life who took time for their careers or waited for the right partner sand then gave birth to their bundles of joy. So we need to remember that statistics are just that: a mathematical analysis of trends and relationships among variables. They’re meant to inform our choices, not to describe each of us perfectly.
Also, our health habits play into pregnancy, and, unlike our preset egg supplies, we actually have control over this part. One of the reasons fertility goes down and pregnancy risks go up with age is that, as we get older, we’re more likely to see the accumulated effects of bad practices like smoking or an unhealthy diet and also to have our overall health docked by conditions like high blood pressure or diabetes. When we take care of ourselves, we’re also staying just a bit ahead of the numbers.
So you can’t ignore the fact that, statistically speaking, fertility peaks in our 20s and slides after that. If you want the best numbers on your side, you start early. Indeed, if I let the numbers dictate, I would have been making babies around the time I was busy cramming for bio finals in my dorm room.
Instead, like many, I waited until my 30s. And if I have a second child, I will have dipped into a whole new fertility bracket. I’m not oblivious to the numbers, but I also know nothing cataclysmic happened to my ovaries on my 35th birthday. Life is complicated, and there are so many pieces to consider: career, finances, health, relationships. We have to acknowledge biological facts, but in the end, they are just one piece of a very intricate puzzle.