Some women have no idea when they've ovulated. Others can tell the exact moment it happened. In a typical menstrual cycle, an egg grows within a follicle in the ovary for 2 weeks, starting on the first day of your menses. Then, a hormone called luteinizing hormone (LH) rises dramatically and triggers the release of the egg. The release of the egg is called ovulation.
When you ovulate, the egg is picked up by the fallopian tube. If a man's sperm makes its way to the same spot within the next 6 to 12 hours, it may fertilize that egg. You're not actually pregnant until the fertilized egg, called a zygote, travels the rest of the way down the fallopian tube and attaches itself to the wall of your uterus. In unfortunate cases it attaches elsewhere and causes an ectopic pregnancy.
The catch: The average egg lives for fewer than 24 hours, and the average sperm lives for less than 72 hours. So, the sperm must fertilize the egg during the first few hours after sex if you're going to conceive. The moral of the story: If your goal is to get pregnant, you should aim to make love at least every other day during the middle of your cycle. Studies have shown that sex must occur before ovulation in order to become pregnant. For most couples, if the usual time of ovulation is known, having sex at least every 2 days starting 3 to 4 days before the usual ovulation time and continuing 3 to 4 days afterwards is optimum. Some couples have been told that the chance of pregnancy is reduced by having sex often. That is not true. While having sex more often than every 2 days may not increase your chance of becoming pregnant, it will not decrease that chance either.
Use the following tool as a quick way to get an idea of when you ovulate. Please note that ovulation is tricky to pinpoint; see our timing and fertility article for more information.
NOTE: Many factors can affect the accuracy of this tool, including irregular menstrual cycles. This calculator should not be used as a method of preventing pregnancy.
Reviewed By: John D. Jacobson, MD, Professor of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda Center for Fertility, Loma Linda, CA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.