If a woman does not have a period, it depends on what time of the year she is in. Women in puberty do not have a period yet and the function of the ovaries is not yet developed, so they will not get pregnant if they have intercourse at this time, but it is not recommended to have sex too early because it can cause infection in the reproductive system and other diseases, which can have an impact on the body. If possible, you should wait until you are an adult before having sex. For women who are breastfeeding, this is the postpartum period, during the breastfeeding period menstruation has not recovered, if you have intercourse, there is a chance of pregnancy, although breastfeeding does not resume menstruation, but it does not mean that there will be no ovulation, at this time if you do not intend to prepare for pregnancy, you should take oral emergency contraceptives, emergency contraceptives can not be breastfeeding within 48h after the end of oral. In menopausal women, the function of the ovaries will be in decline and will cause amenorrhea, and the maturity of the follicles will decrease at this time, so intercourse will not be pregnant.