You may not be looking to get pregnant right now, but it’s important to understand what can affect your success if you do decide you want to start a family—and what you can do now to prepare.

1. Age.
If you’ve heard it once, you’ve heard it a million times: the most important factor in fertility is age. Women are born with all the eggs they’ll ever have, and as we age, the quantity and the quality of those eggs both decline. Menopause may not happen until your early 50s, but for most women, fertility begins to decline sharply around age 35. By age 40, a woman’s chance of getting pregnant is less than 5% per menstrual cycle, meaning fewer than 5 out of 100 women are expected to be successful each month they try.

In vitro fertilization can help, but it’s not a magic pill that can reverse the effects of aging—according to the American Society for Reproductive Medicine, birth rates for women undergoing in vitro fertilization decline dramatically with age; by age 43, the chance of becoming pregnant through IVF is less than 5%—not much higher than the chance of natural pregnancy! Sure, we all know about celebrities getting pregnant in their late 40s or even 50s—but what we don’t know is that often, those celebrities are using eggs donated from younger women. ASRM advises that women over 40 have a much better chance of success with donor eggs.

What can you do?
If you’re thinking of waiting to have kids, freeze! No, literally, freeze your eggs—cryopreservation will prevent them from aging as they would inside your body, so if you do experience difficulty getting pregnant later, you can be your own egg donor. Pretty cool.

2. Genetics.
As with so much of our health, genes strongly influence fertility, including the age of menopause. In fact, you’re six times more likely to experience early menopause (before age 40) if your mother, sister, or grandmother experienced it. Additionally, researchers at Stanford University recently discovered a link between certain genetic markers and hormone levels that suggests our reproductive lifespan may be very nearly fixed by our genetics.

What can you do?
One of the best things you can do is understand your family fertility history, so that you can proactively manage your fertility health. Ask your female relatives about their experience with menopause and fertility—if one or more of them hit menopause prematurely or had difficulty conceiving, you’re at risk, too. If so, talk to your doctor about fertility testing and educate yourself about freezing your eggs, which is a great back-up plan!

3. Hormones.
We’ve talked before about the absolutely crucial role that hormones play in the process of getting and staying pregnant. Hormones are the chemical messengers of the body, flowing back and forth between glands and organs to tell them when and how to kick into gear; any change in your hormones can change the way your body functions. There are many hormones at work in the process of ovulation and conception—like gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), follicle-stimulating hormone (FSH), estrogen, and progesterone—and each of these must be present at the right time, and in the right quantity, to ensure that the process goes smoothly. For example, the right level of progesterone is crucial for ovulation, embryo implantation, and during early pregnancy; not enough, and you could experience infertility or miscarriage.

And if the levels of other hormones not involved in ovulation are too high, that could affect your body’s delicate balance, as well. One example is polycystic ovarian syndrome, a common cause of infertility. PCOS is often marked by the presence of elevated androgens (male sex hormones, like testosterone), which prevent a woman’s body from ovulating properly.

What can you do?
Usually, a gynecologist or endocrinologist can prescribe specific medications to help balance the hormones in your body and allow it to function normally.

4. Anatomical or gynecological issues.
Infertility can result from damage to reproductive organs that occurs with injury or disease. One example is pelvic inflammatory disease, an infection in the upper reproductive system; scar tissue from PID could block a woman’s Fallopian tube(s) and prevent ovulation or pregnancy. Another example is endometriosis, a disorder in which tissue from inside the uterus begins to grow on other organs, causing swelling, cysts, or blockages that might prevent pregnancy in a similar way.

Additionally, some women have congenital structural abnormalities, like a differently-shaped uterus or Fallopian tube defects, that can prevent pregnancy. An abnormality like this is usually present from birth and may not cause any other symptoms—a woman might not even know about it until she tries to get pregnant.

What can you do?
In many cases, such as with endometriosis, a doctor can perform surgery to remove the blockage or correct the abnormality, which may restore the woman’s ability to get pregnant. Because surgery for conditions like endometriosis could involve damage to the ovaries, many doctors recommend women freeze their eggs to preserve their chances at pregnancy. And for some conditions in which the structural problem can’t be fixed, in vitro fertilization offers a way to bypass the problem.

5. Medical history.
Unfortunately, certain medical treatments can jeopardize a woman’s fertility. As mentioned above, surgery to the ovaries—to remove a cyst or treat endometriosis—could damage the ovaries or reduce ovarian reserve. And chemotherapy and radiation, while obviously life-saving treatments for cancer and other illnesses, can destroy or damage a woman’s eggs or cause premature menopause. In fact, egg freezing was initially developed as an way for women who were about to undergo these types of fertility-damaging treatments to preserve their chance at pregnancy later on.

Other medical history, like the presence of an untreated sexually transmitted infection, can also decrease fertility by causing pelvic inflammatory disease (PID) and scarring in the reproductive system.

What can you do?
If you’re about to undergo ovarian surgery, chemo, radiation, or other treatment, ask your doctor how it might impact your chances of getting pregnant in the future. If it poses a risk to your fertility and you might want children one day, you may want to consider egg freezing. And get tested regularly for sexually transmitted infections, even if you’re not experiencing symptoms—some sexually transmitted infections, like gonorrhea and chlamydia, come with no symptoms at all.

6. Lifestyle.
Let’s face it: your age, genetics, and biology have the greatest impact on your fertility—but that’s not to say that your lifestyle has no impact at all. According to the ASRM, up to 13% of infertility may be attributable to cigarette smoking. Smoking depletes the ovarian reserve and causes chromosomal damage to a woman’s eggs, and it’s estimated that women who smoke reach menopause one to four years earlier than nonsmokers. Other lifestyle factors, like being significantly overweight or underweight or having an irregular sleep cycle, could also affect fertility by creating a hormone imbalance.

What can you do?
The good news about lifestyle factors is that their effects are temporary and mostly reversible. Quit smoking now, and your hormone levels should regulate (though the damage to your eggs and ovarian reserve is unfortunately permanent). Get to a healthy weight and settle into a regular sleep pattern and your fertility should return to normal—there’s no evidence that these factors affect your fertility in the long term. Phew!

Learn more about infertility. Learn more about how to extend your fertility lifespan.

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