Several common habits and everyday products can quietly reduce your chances of getting pregnant, even when everything else seems fine. Some are obvious, like smoking and heavy drinking. Others are surprisingly under the radar, like the lubricant you use during sex or how intensely you exercise. Here’s what to cut back on or avoid entirely when you’re trying to conceive.
Using Most Common Lubricants
This one catches a lot of couples off guard. Most popular water-based lubricants contain glycerin, which can penetrate sperm membranes, dissolve the protective coating on sperm tails, and significantly reduce motility. In lab testing, Durex had the worst effect on both sperm motility and vitality, with significant decreases at every time point measured. KY Jelly also reduced progressive sperm motility at both 30 and 60 minutes of contact. Even Vaseline and baby oil showed reductions at certain time points.
If you need lubrication, look for a fertility-friendly option like Pre-Seed, which had the least negative effect on sperm in the same testing. Its formula is designed to match the body’s natural osmolarity, meaning it doesn’t damage sperm cells the way conventional lubricants do.
Taking Ibuprofen Around Ovulation
Over-the-counter pain relievers like ibuprofen, naproxen, and other NSAIDs can interfere with ovulation. Here’s why: after your brain sends the hormonal signal to release an egg, your ovarian cells ramp up production of a specific prostaglandin that triggers the follicle wall to break open. NSAIDs block that prostaglandin production. Some stronger prescription-level anti-inflammatory drugs have been shown to completely block follicle rupture and egg release.
Ibuprofen doesn’t appear to fully block ovulation, but it can reduce ovulation rates and potentially delay the process. The drug has a short half-life of about 90 minutes, so occasional use earlier in your cycle is less concerning. But during the days around ovulation, switching to acetaminophen (Tylenol) is a safer choice for pain relief, since it works through a different mechanism that doesn’t affect prostaglandin production in the ovaries.
Exercising Too Intensely
Moderate exercise supports fertility. Vigorous exercise, past a certain threshold, works against it. A large study tracking women trying to conceive found a clear dose-response pattern: women doing two hours per week of vigorous exercise were 16% less likely to become pregnant than sedentary women over the same period. At three to four hours per week, the reduction jumped to 27%. At five or more hours, it reached 32%.
The underlying issue is hormonal disruption. In one study comparing regular runners (averaging about 20 miles per week) to sedentary women, 58% of the runners showed menstrual cycle abnormalities, including skipped ovulation and shortened luteal phases, compared to just 9% of sedentary women. A short luteal phase doesn’t give a fertilized egg enough time to implant properly.
You don’t need to stop working out. Walking, yoga, swimming, and moderate-intensity strength training are all fine. The concern is with high-intensity cardio and endurance training at volumes above a few hours per week.
Being Significantly Under or Overweight
Body weight affects ovulation through a U-shaped curve. Research on North American women found that the risk of ovulatory infertility increases at both ends of the BMI spectrum: below 20 and above 24. Women with a BMI under 17 had a relative risk of 1.6 for ovulatory infertility, while the risk climbed more steeply for women with a BMI of 27 or higher.
This doesn’t mean you need a “perfect” BMI to get pregnant. Plenty of women conceive outside that range. But if you’ve been trying for a while and your weight is significantly low or high, it’s worth knowing that even modest changes in either direction can restore regular ovulation for some people.
Smoking, Drinking Heavily, or Using Marijuana
Smoking damages eggs, accelerates ovarian aging, and reduces sperm quality. Most people know this. What’s less well known is that marijuana also poses a real concern. Cannabinoid receptors exist throughout the reproductive system: in the hypothalamus, pituitary gland, ovaries, uterus, testes, and on sperm cells themselves. THC interferes with hormonal signaling both centrally (in the brain) and directly at the level of the ovaries and testes. If you use cannabis recreationally, stopping while trying to conceive is a reasonable step for both partners.
Alcohol in moderate amounts hasn’t been definitively shown to prevent conception, but heavy or binge drinking disrupts hormonal cycles and is harmful if you become pregnant before realizing it. Since you won’t know the exact day of conception, keeping alcohol minimal or eliminating it during the trying window is the practical move.
Overheating the Testicles
Sperm production requires temperatures a few degrees below core body temperature, which is why the testes sit outside the body. Repeated heat exposure causes real, measurable damage. In a controlled study, men who sat in a 43°C (about 109°F) water bath for 30 minutes daily over 10 consecutive days experienced serious declines in sperm quality. The good news: the damage was reversible. The bad news: recovery takes weeks to months, since a full sperm production cycle runs about 74 days.
Common sources of scrotal overheating include hot tubs, saunas, laptops placed directly on the lap, and prolonged sitting (particularly relevant for long-haul drivers). Epidemiological data confirms that car drivers, welders, and frequent sauna users consistently show poorer semen quality. If your partner regularly uses any of these, it’s worth making changes well before you start trying, given the long timeline of sperm development.
Ignoring Everyday Chemical Exposures
Bisphenol A (BPA) is an endocrine disruptor that mimics estrogen in the body. It’s found in the lining of canned foods and beverages, plastic food containers, water pipes, thermal receipt paper, dental sealants, and some personal hygiene products. In women undergoing fertility treatment, higher urinary BPA levels correlated with fewer mature eggs and lower peak estrogen levels. Animal research shows BPA reduces the ovarian follicle reserve, increases egg cell death, and damages the support cells that nourish developing eggs. Daily exposure likely chips away at ovarian reserve over time.
On the male side, BPA disrupts testosterone production and interferes with spermatogenesis. At high concentrations, it blocks androgen receptors and impairs the cells responsible for making testosterone.
You can reduce exposure by choosing fresh or frozen foods over canned, using glass or stainless steel containers for food storage, avoiding microwaving plastic, and declining paper receipts when possible. These won’t eliminate all exposure, but they meaningfully reduce it.
Eating High-Mercury Fish Regularly
Fish is generally healthy and provides omega-3 fatty acids that support fertility. But certain species accumulate dangerously high mercury levels, and mercury is toxic to developing reproductive cells. The FDA identifies seven types of fish to avoid entirely: king mackerel, marlin, orange roughy, shark, swordfish, Gulf of Mexico tilefish, and bigeye tuna. These sit at the top of the food chain and concentrate mercury from everything below them.
Lower-mercury options like salmon, sardines, shrimp, tilapia, and canned light tuna are safe to eat two to three times per week and provide real nutritional benefits for both fertility and early pregnancy.
Overdoing Vitamin A Supplements
Preformed vitamin A (retinol), the type found in supplements and animal-sourced foods like liver, becomes a concern at high doses during the preconception window. Doses above 10,000 IU per day have been linked to birth defects in at least one large epidemiological study. The threshold isn’t precisely established for exposures between 10,000 and 25,000 IU per day, but staying at or below 10,000 IU daily from supplements is considered safe.
This applies specifically to preformed vitamin A (retinol or retinyl esters), not to beta-carotene, the plant-based form found in carrots and sweet potatoes. Your body converts beta-carotene to vitamin A only as needed, so it doesn’t carry the same risk. Check your prenatal vitamin label: most quality prenatals keep retinol well within safe limits, but if you’re stacking multiple supplements, the totals can add up.
Stressing Over the Timing
Turning sex into a rigid schedule based on ovulation predictor kits can backfire. Couples who limit sex to a narrow “fertile window” sometimes miss it entirely due to natural cycle variation, and the pressure can reduce sexual frequency overall. Sperm survive in the reproductive tract for up to five days, so having sex every one to two days throughout the middle of your cycle covers more ground than trying to pinpoint a single day. Keeping sex enjoyable rather than clinical also matters for sustaining the process over the months it often takes. Among healthy couples under 35, about 80% conceive within the first year of regular, unprotected sex.