During the preparation period, you can have intercourse once in 3 days, and increase the number of intercourse when you are close to ovulation to improve the chances of pregnancy. Men generally reach saturation of their sperm stores in about 3 days, and too frequent intercourse may lead to low sperm density and poor quality; too little intercourse may lead to sperm accumulation and aging, and an increase in the number of dead and deformed sperm. Therefore, during the preparation period, you can have intercourse regularly for about 3 days and increase the number of intercourse when you are close to ovulation. In the case of regular 28-day menstruation, ovulation is counted from the first day of the next menstrual period, and the countdown of 14 days is the ovulation day, and the first 5 days and the last 4 days of the ovulation day together are called the ovulation period. The first 5 days and 4 days of the ovulation date together are called the ovulation period. Increasing the number of intercourse during ovulation can increase the chance of pregnancy. During the preparation period, the couple should develop good habits, maintain a good mood, engage in regular physical exercise, avoid staying up late and overworking, quit smoking and drinking at least 3 months in advance, and go to the hospital for a comprehensive physical examination to achieve the goal of eugenics.