Fetal ultrasound is a substantiative test performed to evaluate the status of the fetus in the placental sac. The fetal ultrasound technique utilizes sound waves of varied frequency range to produce an image of the fetus, placenta and surrounding amniotic fluid. The image is displayed on a screen attached to the ultrasound machine in a black-and-white format. These images serve as a record of the baby’s status when performed at regular intervals during the pregnancy. Fetal ultrasound also plays a vital role in detection of any problem related to the health of the fetus, such as fetal malformations, or a change in the position of fetus.
Get a fetal ultrasound appointment about seven to 14 weeks after the confirmation of pregnancy. At this stage, the fetal ultrasound will give an estimate of gestational age and help pinpoint a due date.
Observe the change in the diameter of the head of the fetus in week 13 and again at the time close to the time of delivery. Ideally, the difference should be 7 cm.
Compare the length of femur in week 14 to that seen at the time close to the due date. The difference should ideally be about 6 cm.
Take note of the abdominal circumference to get an estimate of the body weight of the baby at the time of birth.
Examine the ultrasound for any malformities. Many 3D ultrasounds even allow you to see if the child will be born with a cleft lip or other aesthetic abnormality.
Examine the ultrasound and locate the fetus (depending on the stage of the pregnancy, the baby could look like a peanut or a small child). Count the number of heads visible to determine the possible presense of multiples.
Determine the localization (or position) of the placenta by locating the edge of the cervix, the fetus, and the black void between the baby and the placental wall.
Examine the amount of amniotic fluid to determine if Hydramnios (too much fluid) or Oligohydramnios (too little fluid present) is present. Both of these conditions can be detected by measuring small pockets of the amniotic fluid and then using that information to estimate the amount of total fluid.