Predicting the best time to have intercourse

Predicting the best time to have intercourse

A healthy woman is only fertile for about six days of each menstrual cycle, around ovulation. Determining when ovulation occurs can help you time intercourse to give you the best chance of conceiving a baby.

To help you identify the fertile window, a range of at-home options are available. These include store-bought hormone tests and methods for monitoring temperature, time, or cervical mucus over your cycle. Downloading a fertility tracker app for your mobile device can make it easier to log your body’s changes throughout the month.

Ovulation charting methods for women

Your temperature when you’re fully at rest—called basal body temperature—rises slightly with ovulation. Measuring and recording your basal body temperature over several months can help you predict your most fertile days.

How it works

  1. Purchase a special basal body thermometer, available at most drug stores 
  2. Record your temperature as soon as you wake each morning 
  3. Note when your body temperature rises—this may indicate that ovulation is taking place 
  4. Time intercourse with ovulation. Women are most fertile 2 to 3 days before their temperature increases and 12 to 24 hours after


  • It’s important to take your temperature around the same time and under the same conditions each morning. Many factors can influence basal body temperature, including drinking alcohol or smoking cigarettes the night before, a poor night’s sleep, fever, or using the bathroom 
  • Because sperm can live for 3 to 5 days inside a woman’s body, having unprotected sex a few days before ovulation could achieve pregnancy 
  • Some women don’t experience a change in body temperature at ovulation. For these women, alternative methods will be more helpful 

To track your fertility in the most accurate way, using a combination of all three methods may be best. This is called the symptothermal method.

Other ways to track ovulation

At-home hormone tests

Ovulation predictor tests are available without a prescription at most drug stores. These usually detect a short ovulation window, 24 to 36 hours, by testing the urine for luteinizing hormone (LH), which surges just before ovulation. The advantage of this test is that it can predict ovulation before it happens, when a woman is at her most fertile.

Ovulation pain (Mittelschmerz)

Some women can experience a very specific abdominal pain for a few hours at the time of ovulation. This is called Mittelschmerz—a German term that means “middle pain.” Women who notice these symptoms strongly should consult a healthcare professional, who may rule out more serious conditions such as ovarian cysts, endometriosis, or other conditions involving the ovaries.