Many couples who want to have children schedule intercourse —- in a variety of ways, oddly often. Some suggest holding back intercourse once a week; some test paper; some ultrasound monitoring, some can feel ovulation, some take temperature, etc. The results vary, but when menstruation comes —- most people hang their heads in dismay. One thing that must be acknowledged is that increasing the number of sexual intercourse and having intercourse during ovulation can increase the probability of pregnancy. In general, sperm can survive in the posterior vaginal vault and cervix of women for more than 48 hours (some reports indicate that sperm survive in the vagina for about 0.5 to 2.5 hours, cervix for 48 hours, uterus for 24 hours, fallopian tubes for 48 hours, and the loss of sperm fertilization ability may be lost earlier), so it is recommended that infertile couples have sex every 2 days before ovulation to keep the fallopian tubes 12 to 24 hours with the presence of sperm; the oocytes have a very short survival time and sex after ovulation often does not result in pregnancy. Some studies have confirmed that sex 5 days before ovulation can lead to pregnancy. If an infertile couple has sex ≤ 2 times a month, it may be a factor in infertility and it is recommended to increase the number of sexual intercourse appropriately. There is also the fact that with the onset of female orgasm, a large amount of love fluid can be secreted, diluting the cervical mucus, which facilitates the entry of sperm, and the uterus presents negative pressure, sucking the sperm into the uterine cavity, even if part of the vaginal outflow is not a problem, blocking the vagina and raising the hips really does not help. In addition the female orgasm comes, the whole body is tense, the mood is definitely different, the egg fertility increases, secrete more nutrients to nourish the sperm, is to raise up and wait for fertilization. So we recommend: increase foreplay time, do not want children in order to have children, entertainment health first, children are just a by-product of sex. But in order to have a child, you can just make more effort at the critical moment! If your period is irregular, you can consider the danger period as: the third day of clean menstruation, a week after.