You are most likely to get pregnant if you have sex within a day or so of ovulation. This is usually about 14 days after the first day of your last period. An egg lives for about 12–24 hours after it is released. For you to get pregnant, the egg must be fertilized by sperm at this time. Sperm can live for up to seven days inside a woman’s body. So if you have had sex in the seven days before ovulation, the sperm will have had time to travel up the fallopian tubes to ‘wait’ for the egg to be released.
Common questions about conceiving
How long it takes to conceive
The majority of couples get pregnant within three months. Your own timeline could be longer if you're older, have certain fertility-unfriendly habits (like smoking), or have a condition that impairs fertility.
Of all couples trying to conceive:
- 30 percent get pregnant within the first cycle (about one month)
- 59 percent get pregnant within three cycles (about three months)
- 80 percent get pregnant within six cycles (about six months)
- 85 percent get pregnant within 12 cycles (about one year)
- 91 percent get pregnant within 36 cycles (about three years)
- 93 to 95 percent get pregnant within 48 cycles (about four years)
If you try for a year without success, it's smart to seek help from a fertility specialist. You might conceive on your own if you keep trying, but in case you have an underlying fertility problem, it's best to get help so you don't waste valuable years as your biological clock continues to tick.
If you're 35 or older, time is even more precious and you should get help sooner: Set up an appointment with a specialist if you're not pregnant within six months.
How do I know when I'm ovulating?
Some women can tell when they ovulate. But most women don't notice any changes at all. If you're thinking about getting pregnant, try to track your cycle for a couple of months. Some signs of ovulation include:
- Increased vaginal discharge that takes on a wetter, egg-white-type quality
- A slight increase (about 0.4 to 1 degree Fahrenheit) in basal body temperature, or BBT, which you can detect by taking your temperature each morning before you get out of bed, one or two days after you ovulate. You can get a good sense of your cycle if you chart your BBT for a few months.
For information on how to track these signs, see our articles on detecting ovulation and basal body temperature and cervical mucus. The book Taking Charge of Your Fertility: The Definitive Guide to Natural Birth Control, Pregnancy Achievement, and Reproductive Health, by Toni Weschler, can also teach you to read your body's signals.
If you still have trouble pinpointing the exact date of ovulation, you might consider trying an ovulation predictor test.
If my periods are irregular, will it be harder for me to get pregnant?
Most women have about 12 periods a year, but some have fewer and some skip months or don't get a period at all. Stress, heavy exercise, dramatic weight loss or gain — all of these can cause interruptions in your period. The more irregular your period is, the more difficult it is to predict ovulation.
Say your cycle is 28 days one month, 21 days the next month, and 32 days the following month. Keep a record of your menstrual cycles for several months. Then subtract 17 from your shortest cycle and 11 from your longest cycle. The days between the two are the ones you're most likely to be fertile.
If your cycles are irregular and more than 35 days apart or longer, you should consider seeing your ob-gyn or a fertility specialist to check for other causes of an irregular cycle, such as polycystic ovarian syndrome (PCOS), ovarian dysfunction, thyroid disorder, excessive weight loss or an elevated prolactin level.
Can't we just try and see what happens?
Of course, you don't have to plot basal body temperature or keep complicated logs if you don't want to. You don't even need to have an orgasm to get pregnant. Try having sex at least two to three times a week consistently, and the law of averages probably will prevail.