There’s a lot of information out there, and we know it can be difficult to sift through it all. That’s why we’re here—to be your fertility guide! Let’s clear up some myths and misconceptions about fertility and egg freezing.
Do women really fall off a ‘fertility cliff’ at age 35?
No, age 35 doesn’t represent some sort of hard stop for your fertile years. In actuality, your fertility is at its peak between your late teens and early 20s and declines gradually throughout your adult life.
However, the downward sloping line between age and fertility does steepen in the mid-30s. While, at age 30, your chance of natural pregnancy is about 20% each month and your chance of pregnancy with in vitro fertilization is about 42% each time you try, by 40, those chances drop to about 5% and 20%, respectively. Additionally, your chances of genetic abnormality—resulting in no pregnancy, miscarriage, or genetic disorders for the baby—increases from 25% to 60–80% in the same decade.
So while 35 isn’t a “cliff,” it is a convenient shorthand for doctors. If you’re thinking about having children after 35, that’s okay—and in fact, it’s becoming the norm in some places (like here in NYC). In fact, it’s been shown that babies born to older moms, who are typically more financially and emotionally stable, get lots of benefits as a result. But experts recommend freezing your eggs while you’re still young, to ensure that if and when you do want to start a family, it’s possible.
Learn more about age and fertility.
Is fertility advice is based on outdated research?
Yes, there’s a commonly cited historical study which reviewed birth records from France between 1670–1829 to determine that birth rates for women over 35 were only about 66%.
Firstly, let’s clarify why that data is useful: data from before the mid-twentieth century is by definition not complicated by the use of reliable birth control or fertility treatment (because neither existed yet). That makes this data, in a sense, more useful, because “natural fertility” and its relationship to age can be inferred very directly.
Additionally, that’s far from the only study to examine the relationship between fertility and age. According to a study of ten populations from across the world between 1600–1950, couples married between age 20 and 24 had a 94% chance of having a child, while couples married between 40–44 had only a 36% chance.
But the best studies are not retrospective (meaning they look at data that’s already happened) but prospective—meaning, in this case, that they track a group of women trying to conceive over a long period of time.
In one such study of 460 women without children and with no other fertility issues, 85% of women aged 30–33 got pregnant within one year, while only about 70% of women aged 34–37, 35% of women aged 38–39, and about 29% of women aged 40–44 got pregnant in the same time period. (This is a very modern study—it was published in 2016.)
In many studies of modern-day women, researchers attempt to eliminate other factors that may affect conception, such as the fertility of the male partner, the desire for pregnancy, and frequency of sexual activity, leaving the focus specifically on the age of the woman. In one example, “Female Fecundity as a Function of Age,” researchers examined the pregnancy rates of healthy women with no other fertility issues, trying to conceive through insemination with healthy donor sperm. The results confirm that pregnancy rates decreased progressively with the increasing age of the woman. “The cumulative pregnancy rate observed across up to 12 insemination cycles was 74% for women younger than 31 years,” the study found, which “decreased to 62% for women aged 31–35 years, and to 54% for women older than 35 years.”
And modern medical technology, like in vitro fertilization, can’t completely solve the problem of age and fertility—a similar pattern of declining fertility can also be seen in studies of IVF success rates. According to a 2010 report from the CDC, “the percentage of IVF (in vitro fertilization) cycle starts that resulted in live births was 41.5% in women younger than 35 years, 31.9% in women aged 35-37 years, 22.1% in women aged 38-40 years, 12.4% in women aged 41-42 years, 5% in women aged 43-44 years, and 1% for women older than 44 years.” (Importantly, the per-cycle rate of pregnancy for patients using donor eggs from younger women is about 50%, regardless of the patient’s age—because what’s most important for a healthy pregnancy is the age of the egg.)
Taking into consideration the results of these many studies, the American Society for Reproductive Medicine estimates that, generally, a woman’s fertility “decreases gradually but significantly beginning approximately at age 32 and decreases more rapidly after age 37 years.”
Learn more about the biological clock.
If Janet Jackson can get pregnant in her 40s, all women can—right?
Janet Jackson announced her first pregnancy at age 49. Actress Marcia Cross had twins at age 44, as did actress Marcia Gay Harden. Late-in-life celebrity pregnancies are in the news consistently. But what most celebrities aren’t telling us is that there’s a very high likelihood they used assisted reproductive technology, like in vitro fertilization—or, more likely in the case of late-40s pregnancies, an egg donor—to achieve these pregnancies.
That’s just the science of age and fertility—and while celebrities are exceptions to a lot of rules, the decline of fertility over time isn’t one of them. And, unlike everyday women, celebrities have thousands of dollars to dedicate to these fertility treatments, which aren’t always covered by health insurance.
It’s understandable that they don’t talk about how they got pregnant; there’s unfortunately still a stigma surrounding infertility, not to mention age (plus, we’re already privy to way too much of celebrities’ personal lives—they deserve at least some privacy). But reproductive endocrinologists (fertility doctors, like those on our team here) unfortunately see way too many women who believe that these high-profile pregnancies are representative of the true relationship between age and fertility.
Does the chance of miscarriage or birth defects really increase with age?
In addition to having fewer eggs as they get older, women also experience reduced egg quality. Egg quality refers to the state of an egg as being genetically normal or genetically abnormal, and as a woman ages, a higher percentage of her egg reserve is genetically normal. If an egg is normal, great—you have a healthy pregnancy. But if it’s not? Abnormal egg cells typically don’t fertilize or implant in the uterus (resulting in infertility), but in the rare case they do, they can result in miscarriage or genetic disorders like Down syndrome.
According to lab studies, the likelihood of an embryo being genetically normal (or “euploid”) decreases from 70–80% for women under 30 to less than 10% for women in their mid to late 40s.
The risk of genetically abnormal pregnancy rises from 1 in 475 at age 25 to 1 in 18 at age 45. This goes hand-in-hand with significant increases in the risk of miscarriage and birth defects, such as Down syndrome.
In a study that examined the relationship between maternal age and miscarriage in over 1 million pregnancies, it was found that there was a steep increase in pregnancy loss for women over 35. Risk of miscarriage for women over 40 were over 1 in 2; by age 45, over 90% of pregnancies ended in miscarriage.
Rates of Down syndrome increase significantly, as well, from 1 in 1,200 for mothers aged 25 to 1 in 30 for mothers aged 45, according to the National Down Syndrome Society.
So yes, doctors see a significant increase in risk in miscarriage and birth defects in older mothers. Again, it’s not a “cliff”—it’s a progressive decrease that begins at the time of “peak” fertility in our teens and early 20s and accelerates in our mid-to-late 30s.
The really good news for women who might want to become mothers later is that freezing eggs when they’re still young and healthy preserves their health until they’re ready to use them. Learn more about why egg freezing works.
Women don’t need to worry about egg freezing until they’re in their late 30s, right?
The ideal age to freeze your eggs is 27–35. Unfortunately, many women don’t begin to think about egg freezing in their 20s or early 30s. And many OB/GYNs, the doctors that women trust most to get this kind of information, are hesitant to talk with patients about fertility unless they ask specifically. Many doctors don’t bring up the option of egg freezing at all; for those who do, they often bring it up with patients in their late 30s, who are already experiencing a diminished reserve of healthy eggs in their ovaries.
Yes, many women have successful egg freezing cycles at later ages. But egg freezing is most effective—and often least expensive (because it typically requires less medication and fewer cycles)—when the woman freezing is closer to her peak fertility. Think about it this way: the time that you’re most likely to get pregnant is also the best time to freeze your eggs.
Egg freezing is not an infertility treatment, it’s a preventative and proactive treatment—ideally, it’s used to preserve healthy, young eggs for later on. We don’t recommend that women wait to freeze until they start to worry about their fertility. If you think you may freeze your eggs one day, it’s worth it to do it sooner, rather than later—your eggs will never be healthier or more plentiful than they are right now!
Learn more about egg freezing myths.
Is it true that the chance of success with egg freezing is only 2–12%?
That figure represents the chance of pregnancy per egg—not the chance of pregnancy overall after egg freezing. Egg freezing success rates depend on two main factors: the age of the woman when she froze and how many eggs she froze. At Extend Fertility we encourage women to freeze at least 12 eggs, which can typically be done in one treatment cycle. (This is reflected across the industry—very few doctors would advise a woman to freeze as few as 2, 4 or 6 eggs.)
Remember—even at peak fertility, a woman doesn’t have a 100% of pregnancy during each ovulation cycle (more like 25%). So it’s important to compare the chance of pregnancy per frozen egg to the chance a woman has of getting pregnant naturally, each month, at the age of 30 (about 20%)—or the 15% chance she has at age 35—or the 5% chance she has at 40. (See the chart above that outlines the monthly chance of natural pregnancy by age.)
The latest study examining egg freezing success rates considers both a woman’s age at the time of freezing and how many eggs she freezes. This model predicts that women under 35 who freeze 10–20 eggs have between a 70 and 90% chance of at least one live birth later on.
Learn more about egg freezing success rates.
Are you ready to learn more about your own fertility health and the egg freezing process? Schedule a free call with a fertility advisor to get your questions answered!