Most causes of infertility are either preventable or manageable, and the steps that protect your fertility are surprisingly straightforward. They come down to timing your family planning around biological realities, keeping your body in good reproductive shape, avoiding a short list of known hazards, and catching problems early. Here’s what actually moves the needle.
Understand How Age Affects Your Window
Age is the single biggest factor in fertility, and it matters more than most people realize. A healthy 30-year-old woman has roughly a 20% chance of conceiving in any given month. By 40, that drops below 5%. Even with IVF, success rates for women over 40 are generally under 20% per cycle, and by 43, they fall below 5%. This decline is driven by both the number and genetic quality of eggs, which decrease steadily from birth and accelerate in the mid-30s.
Men aren’t exempt. A study of nearly 7,000 sperm samples found that total motility (how well sperm swim) drops significantly after 35, and DNA damage in sperm rises substantially after 40. Sperm concentration stays relatively stable, but the quality of each individual sperm cell declines. If you’re planning to have children, the most powerful thing you can do is factor age into that timeline for both partners.
Get to a Fertility-Friendly Weight
Body weight directly affects reproductive hormones. Fat tissue produces estrogen, so carrying too much weight can throw off the hormonal signals that trigger ovulation. Being significantly underweight does the same thing by suppressing those signals entirely. Research on IVF outcomes shows that pregnancy rates drop meaningfully once BMI reaches 28 or higher, and the standard healthy range of 18.5 to 25 is associated with the best conception odds.
For men, excess weight raises scrotal temperature, lowers testosterone, and can reduce sperm quality. You don’t need to hit an exact number on the scale. Even modest weight loss (or gain, if you’re underweight) can restore normal ovulation and improve sperm parameters within a few months.
Protect Yourself From STIs
Untreated bacterial infections, particularly chlamydia and gonorrhea, are a major preventable cause of infertility. In women, these infections can travel upward into the uterus and fallopian tubes, causing pelvic inflammatory disease (PID). PID creates scar tissue that physically blocks sperm from reaching an egg or prevents a fertilized egg from reaching the uterus, leading to ectopic pregnancy. The damage is often permanent.
The tricky part is that chlamydia frequently causes no symptoms at all, so it can silently scar the reproductive tract for months or years before anyone notices. Regular screening if you’re sexually active with new partners, and consistent condom use, are the most effective ways to prevent this kind of damage. If you do test positive, prompt antibiotic treatment can clear the infection before it spreads.
Reduce Your Chemical Exposure
A class of chemicals called endocrine disruptors can interfere with reproductive hormones by either mimicking them or blocking their receptors. The most well-studied culprits include BPA (found in some plastics and can linings), phthalates (used to make plastics flexible), and flame retardants known as PBDEs. BPA exposure during reproductive years has been shown to compromise embryo implantation and is associated with ovarian cysts. Phthalates can alter the development of sperm and egg precursor cells. Even low-level lead exposure changes reproductive hormones and may shorten a woman’s reproductive lifespan.
You can’t eliminate exposure entirely, but practical steps help: avoid microwaving food in plastic containers, choose fragrance-free personal care products (fragrance formulas often contain phthalates), opt for glass or stainless steel food storage, and filter your drinking water. These changes reduce your daily chemical load over time.
Watch Your Alcohol Intake
Caffeine gets a lot of worry, but research from Harvard suggests it doesn’t meaningfully affect conception odds for either partner. Alcohol is the real concern. Women undergoing fertility treatment who drank more than seven alcoholic drinks per week were 7% less likely to conceive. When their male partners drank that same amount, the chance of a live birth dropped by 9%. Seven drinks a week is about one per day, so the threshold isn’t extreme. Keeping intake moderate, or cutting it out while actively trying, is a simple way to avoid an unnecessary drag on your odds.
Keep Sperm Cool
Sperm production requires temperatures slightly below core body heat, which is why the testicles sit outside the body. Research shows that raising scrotal temperature by just 1.5 to 2 degrees Celsius is enough to inhibit sperm production. Common culprits include tight underwear, prolonged hot baths, laptop use directly on the lap, and occupations that require sitting for long stretches.
Switching to looser-fitting underwear, taking breaks from sitting, and keeping laptops on a desk or table are easy fixes. Sperm take about 74 days to fully develop, so the benefits of these changes show up roughly two to three months later.
Manage PCOS and Endometriosis Early
Polycystic ovary syndrome (PCOS) and endometriosis are two of the most common reproductive conditions, and both can quietly reduce fertility if left unaddressed. PCOS disrupts ovulation, meaning eggs aren’t released on a regular schedule. Signs include irregular or absent periods, acne, and excess hair growth. Endometriosis causes tissue similar to the uterine lining to grow in places it shouldn’t, leading to inflammation, scarring, and pain, particularly during periods.
These conditions can overlap. Research published in Fertility and Sterility found that a significant proportion of infertile women with PCOS also had unrecognized endometriosis, masked by heavy or irregular bleeding. If you have painful or very irregular periods, getting evaluated sooner rather than later gives you more options. PCOS often responds well to weight management and medications that restore ovulation. Endometriosis may require surgical treatment to improve pregnancy outcomes, and earlier intervention preserves more healthy tissue.
Consider Supplements That Have Evidence
CoQ10 is one of the better-studied fertility supplements. It supports the energy production that egg and sperm cells need to develop properly. A systematic review found that CoQ10 supplementation increased pregnancy rates in people undergoing assisted reproduction, with study doses ranging from 180 mg to 1,200 mg per day. There’s no universally accepted fertility dose yet, but it’s one of the few supplements with real clinical data behind it.
Folic acid is essential before and during early pregnancy to prevent neural tube defects, and most guidelines recommend starting it at least one month before trying to conceive. For men, zinc supports testosterone production and sperm development. A balanced diet rich in leafy greens, nuts, seeds, fish, and whole grains covers many of the micronutrients linked to reproductive health, and targeted supplements can fill specific gaps.
Know When to Get Evaluated
The American College of Obstetricians and Gynecologists recommends a fertility evaluation if you haven’t conceived after one year of regular, unprotected sex. If you’re over 35, that timeline shortens to six months. If you’re over 40, it’s worth pursuing an evaluation right away rather than waiting. These timelines exist because earlier evaluation means more treatment options and better odds with those options. A basic workup typically involves hormone blood tests, an ultrasound to check the ovaries and uterus, and a semen analysis for the male partner. Most causes of infertility are identifiable with these straightforward tests.