Celebrities can hardly sneeze without someone noticing, so when famous women age 40 or over get pregnant, word spreads fast. Their ranks include Courteney Cox and Celine Dion, who both used in vitro fertilization to have children.
It’s certainly not impossible for women over 35 or even 40 to give birth, but celebrities in the limelight for doing so are the exception, not the rule — and they can give women the wrong impression about their own chances.
Past age 35, a woman’s likelihood of conceiving naturally declines. Her likelihood of conceiving a child through in vitro fertilization (IVF) using her own eggs declines too.
A 30-year-old woman has about a 20% chance of becoming pregnant without assistance every month she tries, according to the American Society for Reproductive Medicine (ASRM). By age 40, that chance has declined to 5%.
A woman’s age-related decline in fertility has been linked to a gradual decrease in the number and quality of cells that can mature into eggs in the ovaries (known as ovarian reserve), notes a report from the ASRM and American College of Obsetricians and Gynecologists (ACOG).
Women are born with 1-2 million of these cells, and about half are left by puberty. The number will continue to decline through the reproductive years, leaving about 1,000 still around at menopause. Fertility begins to decrease at age 32, and the downward slope gets steeper after age 37, according to the report.
Dwindling ovarian reserve “doesn’t mean you cannot get pregnant,” Dr. Pasquale Patrizio, director of the Yale School of Medicine In Vitro Fertilization and Preservation Program, told Business Insider.
He likened ovarian reserve to the amount of gas left in the tank of a car: even if the tank is close to empty, you don’t know how many more miles you might be able to get out of it. Still, the fact remains that the amount of “gas” a woman has in her tank decreases with age.
While tests exist to estimate ovarian reserve by various hormone levels, these tests were developed to help physicians decide what dose of medication to give patients for IVF, not to help patients figure out their chances of conceiving, says Dr. Samantha Pfeifer of Weill Cornell Medical College.
“It is not clear that any of these [tests] predict who is fertile and who is not,” she told Business Insider in an email. “The most important predictor of fertility is age.”
Technology doesn’t fully circumvent age
Even when women turn to IVF, age still affects their chances of getting pregnant.
IVF is a procedure in which eggs are taken from a woman’s ovaries and fertilised with sperm in a petri dish. Then one or more fertilised embryos are placed in the woman’s uterus, where one will hopefully implant and grow into a baby. That whole process is one cycle and costs an average of $US12,400, according to ASRM.
A woman’s age is the most important factor influencing the success of IVF when she uses her own eggs, according to the Society for Assisted Reproductive Technology (SART), the professional organisation for IVF clinics. The graph below makes this clear:
Around 40% of IVF cycles result in babies for women aged 32 and younger. Not even 10 years later, for women aged 40, that success rate is cut in half to less than 20%.
A live birth rate of about 20% for 40-year-old women is not quite as bad as it sounds — remember it’s about the same chance a healthy, fertile 30-year-old woman has of becoming pregnant every month she tries, and far more than a 40-year-old woman’s chance without IVF.
But when women see headlines about celebrities having twins in their 40s, it can seem that they got pregnant with little or no trouble all. The numbers show, however, that these women are lucky exceptions, not models of what most women can expect to happen for them.
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