An ultrasound examination is carried out to determine, among other things, the age of the fetus and calculate the date of birth. The survey is voluntary and five percent of all pregnant women in Sweden choose not to carry it out.
Ultrasound is a high frequency sound wave that can be emitted from a device. The waves are reflected in the tissue and bounce back to the apparatus, where they are measured and an image is created. Different tissues, such as fat and water, reflect the sound differently, which makes it possible to separate the tissues in the picture.
Why is ultrasound examination used in pregnancy?
The study is mainly conducted to assess the age of the fetus and thus calculate the date of birth, ascertain whether there is a twin pregnancy and determine the location of the placenta. In many countries, the study is used as fetal diagnostics. In Sweden, this is not the stated purpose, however, the fetus is estimated in 80 percent of cases and some malformations can be revealed.
Who undergoes ultrasound examination?
95 percent of all pregnant women in Sweden undergo an ultrasound examination sometime during pregnancy. The study is voluntary and is carried out sometime between pregnancy week 16 and 18.
How does an ultrasound scan work?
During the very first pregnancy period, before week 10, information is most easily obtained by ultrasound examination via the vagina, so-called vaginal ultrasound. The examination goes on as a gynecological examination. The doctor inserts a vaginal scanner into the vagina. Although the fetus is only a few millimeters large, it can be seen on the screen.
Later in pregnancy, the examination is done via the outside of the abdomen. The pregnant woman lies comfortably on her back and ultrasound gel & eacute is applied. Then the scanner is passed over the stomach until you have found the fetus and the placenta. In most places, the pregnant woman can follow the survey on a TV screen. Then the pregnant woman can usually get, or buy, pictures of the fetus.
What is being investigated in an ultrasound scan?
In the study that takes place around pregnancy week 16-18, the fetus is systematically examined. You measure the head and the femur. You can also see if the fetus has arms, legs, stomach, bladder and kidneys and if there are signs of spinal or herniated abdominal wall. Likewise, brain and heart evaluations are made. The size of the fetus is assessed in relation to how far the pregnancy is, and if the calculations are not correct, the date of the expected birth is changed.
The placenta’s location is determined, but only later in pregnancy can one assess whether it is normal or if the placenta is wrong.
In the latter part of pregnancy, ultrasound examination is also used to assess whether the fetus is growing normally. It is also possible to examine the influx of blood into the baby’s umbilical cord. In this way, one assesses whether the placenta is functioning properly, that is, if it carries enough oxygen and nutrients to the child.
Is ultrasound scanning a guarantee that the fetus is normal?
Ultrasound examination gives a good picture of the fetus, but you have to be aware that not even the most capable doctors can find every small abnormality that can be found in the fetus.
Is ultrasound scanning dangerous for the fetus?
During all the years that ultrasound examinations have been used, there have been discussions about whether it can harm the fetus. An international working group has been monitoring reports of adverse effects, and they have found no evidence that ultrasound would be dangerous.