Determining whether you are ovulating or not is very important for couples who want to have children. If you don’t know when pregnancy will begin, you can refer to the following methods to determine ovulation:

2. Use an egg detector: An egg detector can determine when ovulation is occurring. This tool usually has a display and a pen that measures the number of eggs in a woman's body. During ovulation, a peak occurs in a woman’s body, with the highest number of eggs.

3. Observe the menstrual cycle: If the menstrual cycle is 28 days, you can start observing it on the 14th day of the cycle. If the menstrual cycle is 30 days, observation can start on the 16th day of the cycle. Watching your menstrual cycle can help determine when you are ovulating.

4. Take your temperature: Taking your temperature can help determine when you are ovulating. During ovulation, a woman's body temperature will rise by 0.5 to 1 degree Celsius.

5. Refer to the calendar: A calendar can help determine when you are ovulating. Marking a woman's birthday and other important dates on her calendar can help determine when she is ovulating.

None of the above methods are 100% accurate, so if you want to determine when pregnancy will begin, it's best to consult a doctor or a professional fertility counselor.