In addition to your number of viable eggs decreasing with age, as eggs get older they’re more likely to have too many or too few chromosomes, the ASRM explains, which can make it harder to become pregnant and carry a pregnancy to term. “[With age], pregnancy rates decline [and]miscarriage rates increase,” Richard J. Paulson, M.D., division chief of reproductive endocrinology and infertility at the Keck School of Medicine of University of Southern California (USC) and director of USC Fertility clinic, tells SELF. By the time you get to be about age 45, the chances of conceiving without assistance are drastically lower than before, Dr. Paulson explains.
This is part of perimenopause, or the time when ovulation and menstruation happen less often, according to the Merck Manual. At this point, your menstrual cycle may get shorter, which means your periods might become irregular. It may still be possible to get pregnant naturally at that point, but it’ll be much more difficult. “With irregular cycles, the window of fertility is harder to predict,” Dr. Kodaman tells SELF.
Eventually, when you haven’t had a period for at least a year, you’re officially in menopause. The average age of menopause is 51, the ACOG says.
Since there’s a pretty wide gap between your mid-30s and when menopause sets in, what’s all the fertility-related commotion surrounding age 35?
There is some merit to treating 35 as a fertility landmark, but it’s not as scary as it sounds.
All of the experts SELF spoke to pointed out that this focus on fertility and age 35 isn’t baseless. This notion is founded in science.
“Declining fertility around the age of 35 is not just guesswork,” Joshua Johnson, Ph.D., assistant professor in the division of reproductive sciences at University of Colorado Denver, tells SELF.
As the ASRM notes in their committee opinion on optimizing natural fertility, it can be significantly harder for people with ovaries to get pregnant without assistance after age 35. However, this phenomenon has also been overstated to a potentially alarming point when there’s actually a ton of nuance involved.
In general most people are still fertile and able to get pregnant naturally at age 35, but research shows that egg quantity and quality start to go down “more noticeably” around this age, Mary Ellen Pavone, M.D., associate professor in the division of reproductive endocrinology and infertility and director of in-vitro fertilization (IVF) at Northwestern University’s Feinberg School of Medicine, tells SELF. This can make it harder to get pregnant.
Note that she said “more noticeably.” As we mentioned above, declining fertility is a gradual process that starts around age 30, not one that’s nonexistent until it kicks into overdrive at age 35. Plus a ton of factors can influence fertility in different ways in different people of various ages, like health conditions, anatomical issues, and environmental influences we’ll discuss in some detail down below.
Figuring out the exact rate at which fertility declines by certain ages is actually pretty difficult, the experts explain. Landing on these figures would require a large number of couples having frequent, unprotected penis-in-vagin* sex and reporting this activity honestly and accurately. That’s something researchers can’t easily coordinate. Instead experts have concluded that fertility starts a steeper decline at 35 based on a variety of creative data, Dr. Johnson explains. Some of this thinking is based on studies of historical populations who didn’t use contraception for religious purposes or because it didn’t exist.
