Ovulation refers to the date when an egg is released in a woman's menstrual cycle. It is usually considered to start on the 14th day of the menstrual cycle and last until the 28th day. During this period, women will release an egg every month. If the egg and sperm combine, it can be fertilized in the body and form a fertilized egg, leading to pregnancy.

1. Measure basal body temperature: When women wake up every morning, measure their oral or anal body temperature. Basal body temperature can reflect changes in hormone levels in women, so ovulation can be determined by measuring basal body temperature.

2. Observe the menstrual cycle: If a woman has a regular menstrual cycle, she can determine the ovulation period by observing the menstrual cycle. Generally, women begin releasing eggs on day 14 of their menstrual cycle, so if the cycle is 30 days, ovulation may begin on day 16.

3. Use a pregnancy test stick: If none of the above methods can accurately determine the ovulation period, you can use a pregnancy test stick to test whether you are pregnant. Generally speaking, pregnancy tests can test pregnancy between the 10th and 14th days of a woman's menstrual cycle.