Fertility isn’t fixed. While some factors like age are out of your control, many of the biggest influences on conception are things you can actively change: body weight, diet, exercise habits, exposure to certain chemicals, and how well you time intercourse. Women under 30 have roughly a 25% chance of conceiving each cycle, dropping to about 20% after 30 and just 5% by age 40. Those numbers represent averages, and where you fall within them depends heavily on lifestyle.
Know Your Fertile Window
You can only conceive during a narrow window each cycle, typically about six days long: the five days before ovulation and the day of ovulation itself. Having sex during this window is the single most important factor in getting pregnant, yet many couples miss it entirely or mistime it.
One of the most reliable signs that you’re approaching ovulation is a change in cervical mucus. In the days leading up to ovulation, discharge becomes wetter, more slippery, and stretchy, often compared to raw egg whites. This texture lasts about three to four days and signals your most fertile phase. Estrogen rises before ovulation and triggers this change, creating an environment that helps sperm travel more easily toward the egg. In a typical 28-day cycle, this happens around days 10 through 14, but cycles vary. Tracking your mucus over a few months gives you a personalized picture of when you’re most likely to conceive.
Ovulation predictor kits, which detect a hormone surge in urine, offer another way to pinpoint this window. Using both methods together gives you the clearest signal.
How Weight Affects Conception
A BMI between 18.5 and 24.9 is the range most strongly associated with healthy ovulation and conception. Moving outside that range in either direction makes a measurable difference.
Women with a BMI above 27 have roughly 2.4 times the risk of anovulatory infertility (cycles where no egg is released) compared to women in the normal range. Obesity also raises the odds of miscarriage by about 30% in unassisted conceptions. For men, the picture is similar: obese men are roughly 66% more likely to experience infertility than men at a healthy weight. Excess body fat around the scrotum raises its temperature, which damages sperm quality over time.
Being underweight (BMI below 18.5) also disrupts reproductive hormones and can shut down ovulation. If your periods become irregular or stop altogether, that’s a strong signal your body weight is affecting your fertility. Even modest changes, losing or gaining 5 to 10% of body weight, can restore regular ovulation for many people.
Exercise: Enough but Not Too Much
Regular physical activity improves fertility by regulating hormones, reducing inflammation, and helping maintain a healthy weight. Aim for at least 150 to 300 minutes of moderate-intensity activity per week, or 75 to 150 minutes of vigorous activity. Walking, swimming, cycling, and strength training two or more days a week all count.
There is a ceiling, though. One study found that women who exercised four or more hours per week had lower implantation rates and a higher risk of pregnancy loss. Another found that 60 or more minutes of daily exercise in the year before trying to conceive was associated with increased infertility compared to women who never exercised. The issue isn’t fitness itself but the hormonal disruption that extreme training can cause, particularly suppressed estrogen and missed ovulation. If you’re a heavy exerciser and your periods have become irregular or lighter, scaling back may help restore your cycle.
What Men Can Do
Fertility conversations often focus on the female partner, but sperm quality accounts for roughly a third of infertility cases. The good news: sperm regenerate every 72 days or so, which means lifestyle changes can produce measurable improvements within two to three months.
Smoking is one of the most damaging habits for sperm. Tobacco introduces mutagenic substances like nicotine, cadmium, and lead directly into the bloodstream, where they damage developing sperm cells in the testes. Smokers show about a 5% decrease in sperm motility (the ability of sperm to swim effectively) compared to nonsmokers, along with reductions in sperm count and the percentage of normally shaped sperm. Quitting is one of the fastest ways to improve male fertility.
Heat is the other major factor. Testicles hang outside the body for a reason: sperm production requires temperatures slightly below core body temperature. Frequent hot tub use, laptop use directly on the lap, prolonged cycling, and tight underwear all raise scrotal temperature. Switching to loose-fitting boxers and avoiding prolonged heat exposure gives sperm production better conditions.
Heavy alcohol intake, anabolic steroid use, and certain medications can also suppress sperm production. If you’re trying to conceive, it’s worth reviewing anything you take regularly.
Nutrition That Supports Fertility
No single food will make you fertile, but the overall pattern of your diet influences hormone balance, egg quality, and sperm health. A diet built around vegetables, whole grains, healthy fats (olive oil, nuts, avocado), and lean protein provides the foundation. The so-called “Mediterranean diet” pattern has been linked to better fertility outcomes in multiple studies.
A few nutrients deserve specific attention. Folic acid is essential for early fetal development, and most guidelines recommend starting a supplement (400 to 800 micrograms daily) at least one month before trying to conceive. Zinc plays a role in both egg development and sperm production, and deficiency is relatively common. CoQ10, a compound your cells use to produce energy, has been studied for its role in improving egg quality, particularly in women over 35. Typical doses used in fertility contexts range from 100 to 600 milligrams daily. Iron, vitamin D, and omega-3 fatty acids round out the list of nutrients most commonly linked to reproductive health.
For men, antioxidant-rich foods (berries, leafy greens, tomatoes) help counteract the oxidative stress that damages sperm DNA. Processed meats, trans fats, and high sugar intake have the opposite effect.
Reduce Exposure to Endocrine Disruptors
Certain synthetic chemicals interfere with your hormones in ways that directly affect fertility. BPA (bisphenol-A), found in hard plastics, canned food linings, and thermal receipt paper, is one of the most studied. In women, BPA exposure has been associated with hormonal imbalances, reduced ovarian reserve, and a higher likelihood of conditions like PCOS and endometriosis. In men, it’s linked to sperm abnormalities and altered hormone levels.
Phthalates, found in fragranced personal care products, vinyl flooring, and soft plastics, pose similar risks. You can reduce your exposure by choosing BPA-free containers, avoiding microwaving food in plastic, switching to fragrance-free personal care products, and eating fewer canned foods. These changes won’t eliminate exposure entirely, but they meaningfully lower it.
Alcohol, Caffeine, and Sleep
Heavy drinking disrupts ovulation in women and suppresses testosterone in men. Most fertility specialists suggest limiting alcohol to a few drinks per week or eliminating it entirely while trying to conceive. Moderate caffeine intake (under 200 milligrams per day, roughly one to two cups of coffee) has not been conclusively linked to reduced fertility, though some people choose to cut back as a precaution.
Sleep often gets overlooked, but the hormones that regulate your menstrual cycle, including the one that triggers ovulation, are closely tied to your circadian rhythm. Consistently getting fewer than six hours of sleep disrupts these signals. Seven to nine hours on a regular schedule supports hormonal balance for both partners.
When to Seek Help
If you’re under 35 and have been having regular, unprotected intercourse for 12 months without conceiving, a fertility evaluation is the standard next step. If you’re 35 or older, that timeline shortens to 6 months. These aren’t arbitrary cutoffs. They reflect the reality that fertility declines with age, and earlier evaluation gives you more options. If you have known risk factors, like irregular periods, a history of pelvic infections, or a partner with a prior fertility diagnosis, there’s no reason to wait the full timeline before getting checked.
A basic evaluation typically involves blood work to check hormone levels, an ultrasound to assess ovarian reserve, and a semen analysis for the male partner. These tests are straightforward and can quickly identify whether something specific is getting in the way.