Generally sperm after 48 hours is still fertile, but there are individual differences. Women of childbearing age are advised to have intercourse during the ovulation period to improve their chances of conception. Ovulation occurs about 14 days before the next menstrual period. Ovulation occurs about 14 days before the next menstrual period, and 4 to 5 days before and after ovulation are easy to conceive, and the sperm will survive for about 2 to 3 days after intercourse, so after 48 hours the sperm is still viable and there is still a chance of getting pregnant, but there are also individual differences. For women who have regular menstrual cycles, they can use the basal body temperature method and calendar table method under the guidance of their doctors to predict the ovulation period, in order to guide intercourse and improve the chances of conception. In clinical practice, when the menstrual cycle is long, ultrasound can be used to monitor ovulation to guide coitus. Generally, pregnancy can be confirmed by blood HCG (human chorionic gonadotropin) test about 10 days after intercourse.