15 weeks pregnant can be through the uterus height and abdominal circumference measurement, listening to the fetal heart, ultrasound and other methods to know whether the fetus is good or not. 1. Uterine height and abdominal circumference measurement: 15 weeks pregnant can be measured by the uterine height and abdominal circumference to help determine fetal development, generally 15 weeks pregnant uterus is located between the navel and the pubic symphysis, from the uterus height of about 15-20cm, according to the results of the measurements to determine whether the fetus meets the normal gestational weeks, and indirectly understand the development of the fetus is good. 2. Listening to the fetal heart: 15 weeks pregnant can use the Doppler fetal heart stethoscope to listen to the fetal heart, such as the fetal heart 110~160 beats per minute, indicating that the fetus is good. 3. Ultrasound: 15 weeks pregnant can also go to the hospital for ultrasound examination, which can systematically check the structure of the skull, limbs, abdomen, face, etc., as well as understand the amniotic fluid, placenta, umbilical cord blood flow frequency, etc., according to the results of the examination to determine whether the baby is good or not.