The absence of menstruation during breastfeeding may be due to the suppression of estrogen and progesterone in the body, or it may be caused by pregnancy, the chances of pregnancy are usually not high, but you still need to pay attention to good contraceptive measures. When a woman is breastfeeding, her body secretes more prolactin, which inhibits the secretion of estrogen and progesterone, thus inhibiting the development of egg cells and ovulation, and leading to the absence of menstruation, in which case, she is usually not pregnant. However, during the breastfeeding period, due to the gradual recovery of the woman’s body, the possibility of occasional ovulation can not be ruled out, so during the breastfeeding period, there is a possibility of pregnancy. It is recommended to use contraception when having sex during breastfeeding. If a woman experiences pregnancy reactions such as nausea, vomiting and other symptoms during breastfeeding, it is recommended that she consult a doctor in time, and under the doctor’s guidance, complete the relevant examinations to clarify whether she is pregnant or not.