An ultrasound examination is a useful diagnostic tool that helps the doctor make sure everything is working properly.
The prenatal ultrasound is a special machine (ultrasound scanner), which uses sound waves to reproduce images of the fetus and its internal organs, the placenta and the amniotic sac. Thus, the doctor can make sure that the baby is developing properly and make measurements to calculate its height and weight. The procedure for performing the test is simple and completely painless: The doctor, after applying a gel on the abdomen, so that the machine’s probe (transducer) is properly in contact with the skin, moves the transducer by checking the screen and storing the images. On average, an ultrasound examination takes approximately 15-20 minutes.
When pregnancy progresses smoothly and no problems occur, the first analytical ultrasound is performed usually between the 6th and 11th week. It examines the number of embryos, their location, the age of pregnancy and assesses their viability. In many cases, the ultrasound is performed transvaginally, which provides better images at this stage of pregnancy.
The second ultrasound is performed between the 11th and 14th week and is used to assess placental position and fetal organs development, while any abnormalities are detected. In addition, a special measurement is performed, the “Nuchal Translucency”, which measures the density of the back of the baby’s neck. This ultrasound is combined with a blood test that assesses the likelihood of genetic abnormalities, such as Down syndrome (PAPP-A test). When performing the Nuchal Translucency test, we can also learn the sex of the fetus (with a probability of about 75%).
Between the 20th and 24th weeks, the second trimester ultrasound is performed, which thoroughly monitors the development and detects any abnormalities in the fetal anatomy. All organs (cardiovascular system, digestive system, kidneys and other urinary tract organs, nervous system) are thoroughly tested. In addition, the amount of the amniotic fluid, the position of the placenta, the length and position of the cervix and umbilical cord are assessed, as well as other parameters that give information on the smooth development of pregnancy. In this ultrasound examination you can also find out the baby’s sex (with 100% probability), if you wish.
The next necessary ultrasound is performed between the 28th and 32nd week to assess the development and projection of the fetus, the amount of the amniotic fluid and the placenta. This ultrasound is combined with Doppler, a sound-wave test that monitors blood flow to the fetal and placenta vessels. If there are any complications, such as gestational diabetes, hypertension, preeclampsia, etc., it is possible for the gynecologist to repeat the examination until the date of delivery.
Finally, an ultrasound test may also be used during some surgical procedures, such as amniocentesis and trophoblast acquisition.