To determine if you are pregnant during breastfeeding without a period, you can use early pregnancy test paper, or you can go to the hospital for a blood HCG test and ultrasound examination, and you can also judge based on symptoms such as reduced milk and early pregnancy reaction. During the postpartum period when you are breastfeeding, because your ovaries have not fully recovered, you may not have your period but you may still ovulate, so if you do not take birth control measures, there is a possibility of unwanted pregnancy, and the easiest way to determine this is to use an early pregnancy test, and if there is a positive result, pregnancy can be confirmed. After pregnancy during breastfeeding, the amount of breast milk secretion will decrease, and there will also be nausea, vomiting, darkening of the areola and other early pregnancy reactions, after these manifestations, you can go to the hospital for an HCG test, and if the value is greater than 25 IU/L, pregnancy can be confirmed. You can also have an ultrasound examination and if a gestational sac is found in the uterine cavity, pregnancy can be confirmed.