Weakness in pregnancy can be caused by early pregnancy reaction or other illnesses in the body. 1. Early pregnancy reaction: In early pregnancy, due to the increase in the level of chorionic gonadotropin, some women may experience weakness and may also be accompanied by nausea and vomiting, picky eaters and anorexics, dizziness and drowsiness and other symptoms of early pregnancy reaction. 2. Other diseases: low blood sugar, high blood sugar, high blood pressure, low blood pressure, anemia, thyroid function abnormalities, etc. may lead to weakness after pregnancy. Further blood sugar, blood pressure, blood routine, thyroid function tests are needed to rule out the effect of these diseases. If the symptoms of post-pregnancy weakness cannot be relieved, it is necessary to go to the hospital as soon as possible, and the doctor will formulate an individualized diagnosis and treatment plan according to the specific situation, so as to avoid delaying the condition.