Everything You Thought You Knew About Age and Fertility Was Wrong—35 Is Not a Cliff

What Women Really Think
June 21 2013 8:00 AM

Everything You Thought You Knew About Age and Fertility Was Wrong

pregnant woman
Despite what we've all read and been told, 35 is not a fertility cliff

Photo by Twonix Studio/Shutterstock

I often joke that working in women’s media for six years has made me way too aware about how one’s fertility declines with age. My husband and I decided to start trying to conceive when I was 29, in part, because I knew, from all of the articles I’d read on the job, that my eggs were rapidly shriveling up and dying with each passing day. I should amend that statement. I thought I knew my eggs were rapidly shriveling up and dying. A jaw-dropping new article by Jean Twenge in the Atlantic shows that a lot of what we’ve been told about the fertility plunge that happens to women in their 30s has been highly oversold.

Jessica Grose Jessica Grose

Jessica Grose is a frequent Slate contributor and the author of the novel Sad Desk Salad. Follow her on Twitter.

Here’s just one example of how imprecise the popular literature surrounding fertility is. Facts that I remember parroting to my husband—that I had a 20 percent chance of conceiving each time I ovulated—turn out to be based on no specific published medical literature. The study that Twenge did discover, by biostatistician David Dunson who is now at Duke University, found that:

Advertisement

[I]ntercourse two days before ovulation resulted in pregnancy 29 percent of the time for 35-to-39-year-old women, compared with about 42 percent for 27-to-29-year-olds. So, by this measure, fertility falls by about a third from a woman’s late 20s to her late 30s. However, a 35-to-39-year-old’s fertility two days before ovulation was the same as a 19-to-26-year-old’s fertility three days before ovulation: according to Dunson’s data, older couples who time sex just one day better than younger ones will effectively eliminate the age difference.

Even more shocking is that a lot of the statistics we hear about modern fertility are based on historical data from French birth records from 1670 to 1830. According to Dunson’s research on contemporary women, there is only a 4 percent drop in pregnancy rates from age 28 to age 37. This comes as a huge shock because almost everything I’ve read takes it as a given that age 35 is a huge cliff that you will fall off of with a resounding splat.

It is true that if you have fertility problems, it’s better to know that sooner rather than later, as interventions work more successfully on younger women. And Twenge does bring up the fact that birth defects increase with a mother’s age—though not as much as we might think. The data about all of this is still sparse and we need more research to know more. Some things Twenge’s article doesn’t mention: how pregnancy can affect an older woman’s body differently than it affects a younger woman’s body. And then there are the benefits that are not quite so tangible—enjoying your children for longer; having a greater probability of seeing grandchildren; having your own parents be involved in your child’s life.

That said, it’s wonderful news that the statistics about fertility decline have potentially been exaggerated. Then perhaps we can push back against attitudes that women are “waiting too long” because they’re deluded or selfish or career-obsessed. That won’t be easy, though—there are comments even on Twenge’s piece like, “one thing is choosing not to have babies and another one is to wait too long and then complain that an IVF costs too much or think that your miscarriages are treatable with some sort of ‘cure’. Nope!”

Most women time their children based on a host of factors—economic stability and romantic stability among them. We can’t all snap our fingers and have a good marriage and a stable career in our 20s because that’s the “optimal” age to have children. I’d also love to be able to dance and have really, really thick hair, but that ain’t happening either. It’s good to hear that our bodies will cooperate with the way society has changed. I don’t know that I would have made my choices differently armed with this new knowledge. But I’m glad it’s out there.

TODAY IN SLATE

Sports Nut

Grandmaster Clash

One of the most amazing feats in chess history just happened, and no one noticed.

The Extraordinary Amicus Brief That Attempts to Explain the Wu-Tang Clan to the Supreme Court Justices

Amazon Is Officially a Gadget Company. Here Are Its Six New Devices.

Do the Celebrities Whose Nude Photos Were Stolen Have a Case Against Apple?

The NFL Explains How It Sees “the Role of the Female”

Future Tense

Amazon Is Now a Gadget Company

Food

How to Order Chinese Food

First, stop thinking of it as “Chinese food.”

Scotland Is Inspiring Secessionists Across America

The Country Where Women Aren’t Allowed to Work Once They’re 36 Weeks’ Pregnant

The XX Factor
Sept. 18 2014 11:40 AM The Country Where Women Aren’t Allowed to Work Once They’re 36 Weeks’ Pregnant
Moneybox
Sept. 17 2014 5:10 PM The Most Awkward Scenario in Which a Man Can Hold a Door for a Woman
  News & Politics
The World
Sept. 18 2014 1:34 PM Americans Fault Obama for Giving Them Exactly the Anti-ISIS Strategy They Want
  Business
Moneybox
Sept. 18 2014 2:18 PM The NFL Is Not a Nonprofit So why does it get to act like one?
  Life
Doonan
Sept. 18 2014 2:00 PM On the Death of My Homophobic Dog I named him Liberace, but I couldn’t have chosen a less appropriate namesake for this coarse, emotionally withholding Norwich terrier.
  Double X
The XX Factor
Sept. 18 2014 12:03 PM The NFL Opines on “the Role of the Female”
  Slate Plus
Behind the Scenes
Sept. 18 2014 1:23 PM “It’s Not Every Day That You Can Beat the World Champion” An exclusive interview with chess grandmaster Fabiano Caruana.
  Arts
Brow Beat
Sept. 18 2014 2:32 PM Kern Your Enthusiasm: The Friendliness of Chicago
  Technology
Future Tense
Sept. 18 2014 2:39 PM Here's How to Keep Apple From Sharing Your iPhone Data With the Police
  Health & Science
Bad Astronomy
Sept. 18 2014 7:30 AM Red and Green Ghosts Haunt the Stormy Night
  Sports
Sports Nut
Sept. 18 2014 11:42 AM Grandmaster Clash One of the most amazing feats in chess history just happened, and no one noticed.