The single most effective thing you can do to get pregnant is have sex during your fertile window, which spans the five days before ovulation and the day of ovulation itself. For a healthy couple in their late 20s, the chance of conceiving within six months of trying is about 60%, rising to nearly 80% within a year. Beyond timing, your weight, diet, habits, and even your partner’s lifestyle all meaningfully shift those odds.
Know Your Fertile Window
You have roughly six days per cycle when sex can lead to pregnancy. Sperm survive in the reproductive tract for up to five days, but an egg is viable for only about 12 to 24 hours after it’s released. That means the highest-probability days are the two to three days leading up to ovulation and ovulation day itself.
For women with a 28-day cycle, ovulation typically falls around day 14, but this varies widely. On any given day between days 6 and 21 of the cycle, at least 10% of women are in their fertile window. The percentage peaks on days 12 and 13, when about 54% of women are at their most fertile. So if your cycle is irregular or you’re not sure when you ovulate, having sex every one to two days throughout the middle stretch of your cycle covers the most ground.
One reliable physical signal: cervical mucus. As estrogen rises before ovulation, your discharge becomes clear, stretchy (it can stretch over an inch between your fingers), and slippery. When you notice this type of mucus, you’re likely in your most fertile days. After ovulation, progesterone rises, and the mucus dries up or becomes sticky and opaque. Ovulation predictor kits, which detect a hormone surge in urine, are another option for pinpointing the window.
How Often to Have Sex
During the fertile window, having sex every day or every other day gives you the best chance. There’s no meaningful difference between daily and every-other-day in terms of conception rates, so do whichever feels sustainable. Outside the fertile window, frequency doesn’t matter for conception, though regular sex throughout the cycle means you’re less likely to miss the window entirely if your ovulation date shifts.
Get to a Healthy Weight
Body weight has a strong, U-shaped relationship with fertility. Being significantly underweight disrupts the hormonal signals that trigger ovulation, sometimes stopping it entirely. On the other end, higher body weight also interferes with the same hormonal system, leading to irregular periods and missed ovulation. A large analysis of U.S. women found that each unit of BMI below about 19.5 was associated with a 33% increase in infertility risk, while each unit above that point raised the risk by about 3%.
You don’t need to hit a precise number. The practical takeaway is that both extremes matter. If you’re underweight, gaining even a small amount of weight can restore regular cycles. If you’re carrying significant extra weight, losing 5 to 10% of your body weight often improves ovulation.
Start Folic Acid Before You Conceive
The U.S. Preventive Services Task Force gives its strongest recommendation (Grade A) that anyone planning pregnancy take 400 to 800 micrograms of folic acid daily. This B vitamin dramatically reduces the risk of neural tube defects like spina bifida. The key detail most people miss: you need to start at least one month before conception and continue through the first two to three months of pregnancy, because the neural tube forms very early, often before you even know you’re pregnant. A standard prenatal vitamin typically contains the right amount.
Cut Back on Caffeine and Alcohol
The current guideline from the American Congress of Obstetricians and Gynecologists is to keep caffeine under 200 milligrams per day while trying to conceive. That’s roughly one 12-ounce cup of coffee. For alcohol, the CDC’s position is blunt: there is no known safe amount of alcohol during pregnancy or while trying to get pregnant. You don’t need to panic about a glass of wine, but regular drinking is worth cutting back on or stopping altogether.
Your Partner’s Health Matters Too
About a third of fertility problems involve the male partner, so this isn’t just about what you do. Smoking cigarettes is linked to a drop in sperm count of nearly 10 million per milliliter, along with reduced motility and abnormal shape. Couples where the male partner drank more than 20 units of alcohol per week took significantly longer to conceive. And men who are obese are twice as likely to have extremely low or absent sperm counts compared to men at a normal weight.
Heat is another factor. Sperm production requires temperatures slightly below core body temperature, which is why the testes sit outside the body. Laptops placed directly on the lap generate enough heat to raise scrotal temperature, and one study found that sperm exposed to a Wi-Fi-connected laptop showed decreased motility and increased DNA damage. Keeping phones out of front trouser pockets and using a desk or table for laptops are simple adjustments.
Reduce Exposure to Hormone-Disrupting Chemicals
Certain everyday chemicals mimic or block your hormones, and they can affect both egg and sperm quality. BPA, found in some plastics, canned food linings, and receipt paper, has been shown to compromise embryo implantation. Phthalates, common in flexible plastics and fragranced personal care products, are another concern. Women under 40 working in the plastics industry in Denmark were more likely to need fertility assistance than women with no occupational exposure.
Practical steps to limit exposure include avoiding microwaving food in plastic containers, choosing fragrance-free products when possible, opting for glass or stainless steel food storage, and washing hands after handling receipts. You can’t eliminate all exposure, but reducing the biggest sources helps.
What Your Odds Look Like by Age
Age is the single strongest predictor of how quickly you’ll conceive. A large North American study tracked couples actively trying and found these cumulative pregnancy rates after 12 cycles of trying:
- Ages 25 to 27: 79% conceived within a year
- Ages 28 to 30: 78%
- Ages 31 to 33: 77%
- Ages 34 to 36: 75%
- Ages 37 to 39: 67%
- Ages 40 to 45: 56%
Fertility stays relatively stable through the early 30s, then begins a more noticeable decline after 35, with a sharper drop after 40. Women in the 40 to 45 group had about 60% lower cycle-by-cycle fertility compared to women in their early 20s. These numbers reflect natural conception without fertility treatments.
When to Get a Fertility Evaluation
If you’re under 35 and have been having regular, well-timed sex for 12 months without conceiving, it’s time to see a specialist. If you’re 35 or older, that timeline shortens to 6 months. For women over 40, the American Society for Reproductive Medicine recommends more immediate evaluation. And if you have a known condition that affects fertility, such as endometriosis, PCOS, or a history of pelvic surgery, there’s no reason to wait. Both partners should be evaluated, since male factors contribute to roughly half of all fertility cases.