Intercourse within 12 hours after ovulation is generally the most likely time for conception. During the pre-ovulation and ovulation periods, the cervical mucus changes from a gel-like state to a watery lysate under the influence of estrogen in the body, which facilitates the entry of sperm into the uterine cavity, and the ectocervix tends to expand gradually during this period. At the time of ovulation, the diameter of the ectocervix can reach 3 mm, and the cervix is relatively soft at this time, making it easy for sperm to pass through. After ovulation, the ectocervix gradually shrinks, while the tension of the cervix increases, which is not conducive to the passage of sperm. Secondly, since sperm can survive for 2-3 days after entering a woman’s genitals, having intercourse 1-2 days before and after the day of ovulation is very likely to result in pregnancy, especially within 12 hours after ovulation, when the chances of conception are higher. If you want to prepare for pregnancy, you should adjust your work and rest schedule and stop smoking and drinking to improve the quality of your eggs and sperm and increase your chances of conception; if your menstrual cycle is disordered, you can use ovulation test strips or ultrasound to monitor ovulation.