Pregnant women with thick belly fat can not see the four-dimensional, it is recommended to pay more attention to diet, weight control and then four-dimensional ultrasound examination, still unsuccessful, it is recommended to choose the magnetic resonance examination. Four-dimensional ultrasound examination during pregnancy, can be clear whether the fetus has the phenomenon of developmental deformities, if due to the pregnant woman fat layer is too thick to affect the four-dimensional ultrasound examination clarity, it is recommended that pregnant women usually pay more attention to reduce the amount of high-fat, high-calorie food intake, and then again after controlling the weight of the examination. If the examination is still unsuccessful, magnetic resonance can also be chosen to check the condition of the fetus. As magnetic resonance is not affected by the fat layer and has the advantages of safety and no radiation, it can be used as an alternative examination plan.