Unplanned pregnancies can still occur in some women during the time the baby is breastfeeding, i.e. while the woman is breastfeeding. Most women resume ovulation during the postpartum period while breastfeeding in 4-6 months, but it may occur too early or too late. Usually when ovulation resumes during breastfeeding, if the egg is expelled from the ovary, it is picked up by the umbilical end of the fallopian tube and peristaltic movement of the fallopian tube to reach the tubal jugular. If you have intercourse during ovulation, it will easily unite with sperm to form a fertilized egg and thus become pregnant. After childbirth, it takes time for the endometrium to recover and the hormone level in the body has not yet returned to normal, especially for breastfeeding women due to taking care of the newborn, irregular rest or high lactogen production during breastfeeding, which may affect the normal recovery of menstruation. Although a woman’s menstruation does not return to normal, it does not mean that there is no ovulation. Ovulation may also occur during breastfeeding, and an unplanned pregnancy may occur in the event of unprotected sex. Therefore, despite the fact that menstruation does not resume during breastfeeding, ovulation may still occur and pregnancy may occur if no contraceptive measures are taken. Early pregnancy may manifest as less milk or nausea or vomiting, and a blood test for human chorionic gonadotropin is recommended to confirm this. Usually, for women who have no plans to become pregnant or after a cesarean section, strict contraception should be used while breastfeeding, and the appropriate form of contraception for breastfeeding women is condom contraception.