Not ejaculating during the safe period will not cause a woman to become pregnant because there is no sperm to combine with the egg to trigger pregnancy. A woman may get pregnant if she does not use contraception during intercourse, and the probability of conception will be very high if she has intercourse during the woman’s ovulation period. Safe period is further divided into pre-ovulation safe period and post-ovulation safe period. Post-ovulation safe period is safer than pre-ovulation safe period, mainly because women are affected by environmental changes, emotions and other factors, so that ovulation is advanced and pre-ovulation safe period is shortened, so pre-ovulation safe period is not so safe.