Ovulation occurs 14 days before the first day of your next period. For women with a “typical’ 28-day menstrual cycle, this means that ovulation occurs on cycle day 14, where the first day of bleeding is day 1. However, not all women have a 28-day cycle. If you have a 30-day cycle, ovulation would occur on day 16 (30 minus 14) or if you have a 26-day cycle, it would occur on day 12 (26 minus 14).
Some clues that you may be ovulating include a thicker, sticky cervical mucus (resembling egg whites) or a change in basal body temperature (prior to ovulation, basal body temperature measured first thing in the morning declines slightly and immediately after ovulation it rises again). These signs are not always accurate and can be difficult to assess. Cervical mucus and body temperature are subject to wide variation from person to person.
Over-the-counter ovulation detection kits can be purchased that are much better at determining ovulation. These urine tests are used with the first urination of the day and they detect the surge in luteinizing hormone (LH) that occurs the day before ovulation. These are not always accurate, but are much better than basal body temperature or cervical mucus monitoring and they have the benefit of determining ovulation the day before, which is an ideal day to have sex when trying to become pregnant.
If your cycle is irregular, if it is longer than 35 days, or shorter than 21 days, talk to your doctor about how you can determine when you are ovulating, or if you need an evaluation to make sure you are ovulating. We can test your blood for a surge of progesterone about 8 days after the suspected day of ovulation to confirm ovulation and there are medical treatments to help you ovulate if you do not.