The lack of weight gain during pregnancy may be due to severe vomiting, slow fetal growth, fetal arrest and other reasons, you should consult a doctor in a timely manner to clarify the cause of the disease, the cause of the targeted treatment. 1. Severe vomiting: In early pregnancy, the pregnant woman’s vomiting is too serious, nausea and vomiting will occur, resulting in decreased appetite, resulting in pregnant women’s weight loss or weight loss, generally a normal phenomenon, the need for timely supplementation of nutrients, small meals, serious medical treatment can be rehydration, symptomatic treatment. 2. slow fetal growth: in the first trimester of pregnancy, fetal growth is slow, generally a month increase of about 500 grams, for pregnant women, this weight gain is less, do not reflect, as well as in the late stages of pregnancy, pregnant women, if the nutrition is insufficient, there will be a lack of significant weight gain. 3. Fetal arrest: If there is a fetal heart but then the fetal heart disappears, it is generally a symptom of fetal arrest, mostly due to chromosomal abnormalities in the embryo itself, should be timely to the hospital, the doctor to make a clear diagnosis, and cooperate with the doctor to deal with the symptoms.