A 3 plus ketone body during pregnancy is serious and suggests that there may be inadequate nutritional intake, diabetic ketosis and other conditions that need to be addressed promptly. The presence of 3 plus sign in urinary ketone bodies during pregnancy is mostly an abnormal presentation and requires blood glucose monitoring of the pregnant woman. For pregnant women without diabetes mellitus during pregnancy, it may be due to severe vomiting during pregnancy and inadequate nutritional intake, which needs to be relieved in time by increasing the amount of food intake. For patients with gestational diabetes, the presence of 3 plus ketone bodies indicates poor glycemic control and possible diabetic ketosis. It may not only cause ketoacidosis which may jeopardize the life of the pregnant woman and the fetus, but also long-term maintenance of this state may result in abnormal development of the fetus or miscarriage and other adverse consequences. Should be timely by the doctor’s guidance closely monitor blood glucose and take diet, medication and other comprehensive treatment, the blood glucose level will be controlled within the appropriate range. Therefore, patients with 3 plus ketones during pregnancy need to seek prompt medical attention in order to identify the specific cause of their condition and be given targeted treatment under the guidance of a doctor.