The items involved in the 42-day postpartum blood test include routine blood test, blood glucose test, blood biochemical test, etc. Whether fasting is needed depends on the situation. 1.No fasting: If only routine tests such as blood test, chest X-ray, electrocardiogram, etc. are involved, and there is no special instruction from the doctor, fasting is not needed, as proper eating helps to stabilize blood glucose, maintain normal metabolism of postpartum women, and help to 2, the need for fasting: if you need to carry out blood glucose, liver function, lipid and kidney function tests, you need to carry out fasting and other tests to ensure that the test results are as accurate as possible, to avoid the interference of extraneous factors on the test results, so that the doctor has a more accurate judgment and analysis of the postpartum recovery. If the examination is not performed according to fasting requirements, food can enter the blood circulation through absorption and metabolism in the gastrointestinal tract, resulting in increased blood glucose and lipid concentrations in the blood, which ultimately makes it difficult to obtain accurate test data; in addition, blood biochemical examination requires judgment and analysis of specimen color, and eating greasy food can lead to cloudy blood, which makes it difficult for the testing personnel to observe the specimen clearly, thus affecting the correctness of the results. It is important to note that the fasting status required for the test is not just not to eat breakfast, but to start fasting after 10:00 pm the night before the test. On the morning of the test, all beverages except water should be prohibited. When having a blood test, you should also consult your doctor in advance to understand the precautions related to the test and follow the doctor’s instructions to obtain reliable results.