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Obstetric ultrasound is an ultrasound imaging technique which is designed to be used in the process of prenatal care. There are a wide range of uses for obstetric ultrasound, and this procedure is a very routine part of prenatal care for many women, especially women in Europe and the United States. Some lay people are familiar with the images generated in the course of an obstetric ultrasound, since the technician often prints out pictures for the parents to see and explains the structures seen on screen to the parents during the course of the procedure.
In ultrasound imaging, high frequency sound waves are bounced off the body to create an image of the contents. This is accomplished by using a transducer which emits waves and then waits to hear the response, generating an image based on the length of the response time and the change in frequency. The result can be a still or moving image, with advanced technology being utilized to create three-dimensional ultrasound images which provide even more detail.
The image may be obtained by coating the belly in a conductive gel and running the transducer along the belly, or by inserting the transducer into the vaginal canal to get a better image, in which case the procedure is known as a transvaginal ultrasound. The resulting image will depict the uterus and its contents, along with surrounding structures.
There are a wide variety of applications for obstetric ultrasound. This type of medical imaging is routinely used to assess a pregnancy, determining how far along the pregnancy is and confirming that the fetus is developing normally. An ultrasound can also be used specifically to check for fetal abnormalities or problems such as a detached placenta. If a mother presents with pregnancy complications which indicate fetal distress, obstetric ultrasound may be used as a diagnostic tool to check on the status of the baby without using invasive techniques.
A doctor can also use obstetric ultrasound to guide specific medical procedures. In prenatal testing which involves taking samples of the amniotic fluid or placenta, ultrasound is used to guide the biopsy needle so that the fetus is not injured. Obstetric ultrasound may also be used in the wake of a miscarriage or termination procedure to confirm that no fetal or placental tissue has been left behind. Failure to check for remaining tissue can lead to infections and complications, including a loss of fertility.
Several government health agencies have specifically recommended against the use of obstetric ultrasound for the purpose of generating keepsake pictures or videos of infants while they are developing. Although ultrasound does not appear to cause harm to developing babies, it has not been proved to be perfectly safe either, which means that it should be avoided unless there is a medical necessity for an ultrasound. In the course of a medically-necessary ultrasound screening, such as a diagnostic screening to confirm the age of the pregnancy, the parents may ask for still images from the ultrasound technician.