If sperm is ejaculated into the vagina, the chances of pregnancy depend on the time of the menstrual period. If you have intercourse during ovulation, the chances of getting pregnant by internal ejaculation are very high, and can be as high as 95%. If you have intercourse during the safe period, then the chance of getting pregnant by internal ejaculation will be very small. So the chances of causing pregnancy will vary depending on the time of intercourse. If you are not planning to get pregnant, it is recommended to use condoms for contraception and to always check for small tears and holes in the condom during use. It is also recommended to wear a condom during the whole process of sexual intercourse.