If an ultrasound is performed in the middle to late stages of pregnancy, the ultrasound indicates that the fetal bladder is visible, which only means that the fetal bladder may be developing normally and does not indicate whether the patient’s fetus is male or female. To determine the sex of the fetus in the middle to late stages of pregnancy, ultrasound is needed to observe the fetal sexual organs. Usually around 14 weeks of pregnancy, the fetal sexual organs are more mature and can be seen clearly. In about 4-5 months of pregnancy, this is the best time to observe the fetal sexual organs, because the sexual organs are already relatively large, and the fetal limbs and trunk are still relatively small, so it is not easy to obscure the fetal sexual canal, so it is easier to see clearly. However, the state explicitly prohibits non-medical requirements to identify the sex of the fetus, so generally doctors will not give a look.