During breastfeeding, due to the influence of the body’s secretion of lactogen on other hormones, menstruation may not occur, or the cycle and volume may be different from before, all of which are normal.
However, it is important to note that if you do not have a period even while breastfeeding, it does not mean that ovulation has not returned and there is a possibility of conception, so you should take care to use good contraception and seek prompt medical attention in case of abnormal bleeding to rule out pregnancy-related illness.