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The First Trimester Scan

The first trimtester scan is a comprehensive fetal anatomy assessment carried out by ultrasound at 12+0-13+6 w.g. The scan can be performed transabdominally or transvaginally. The experience of the examiner and the quality of the ultrasound equipment is of utmost importantance.


The examination is usually performed by 2D ultrasound. Meanwhile, 3D pictures or 4D videos can also be taken. However, due to the small fetal size in the first trimester, a transvaginal scan is often required in order to obtain good visualization.

The main objectives of the first trimester scan at MC MARKOVS are:

  • To perform fetal biometry and to confirm with accuracy the gestational age and the estimated date of delivery;
  • To evaluate all major fetal organs and systems and to exclude the presence of a number of structural defects;
  • To assess the risk of an associated chromosomal abnormality by examining some important sonographic markers;
  • To screen for preeclampsia and fetal growth restriction by Doppler examination of the uterine arteries.

The first objective of the first trimester scan at 12+0-13+6 w.g. is to establish the presence of a viable intrauterine pregnancy, to perform fetal biometry and to specify the gestational age and to determine the estimated date of delivery.


Afterwards, all major fetal organs and systems are evaluated. Head shape, ossification of cranial bones, major brain structures, orbits, face, heart, diaphragm, anterior abdominal wall, stomach, kidneys, bladder and limbs are examined. The localization of the placenta and the number of vessels in the umbilical cord is determined.


The assessment of fetal anatomy in the first trimester can exlclude a number of major fetal structural abnormalities. Timely detection of severe and incompatible with life defects makes possible termination of pregnancy in early gestation.


High-frequency transvaginal fetal echocardiography between 12-13+6 w.g. allows early prenatal diagnosis, resp. exclusion of a number of congenital cardiac malformations. It is usually indicated in high-risk pregnant women.


The specialized ultrasound examination between 12-13+6 w.g. is also used to evaluate some ultrasound markers which can increases the risk of an associated chromosomal anomaly - the increased thickness of the nuchal translucency, the absence of the nasal bone, the tricuspid valve regurgitation, the abnormal blood flow in the ductus venosus, the aberrant course of the right subclavian artery, etc. Thus, the first trimester scan is also used as an effective tool for early ultrasound screening for chromosomal abnormalities, incl. Down syndrome.


Doppler examination of the blood flow in the uterine arteries is also performed during the examination. Abnormal blood flow in the uterine arteries can identify these pregnancies with a higher risk of developing pre-eclampsia, fetal growth restriction, etc. in late gestation.


In overweight pregnant women, it is important to review the fetal anatomy by high-frequency transvaginal (through the vagina) ultrasound between 12-13+6 w.g. In these cases, the evaluation of the fetal morphology through the abdomen is very difficult and adequate visualization can only be planned after 22 w.g.


We offer to all our patients at MC MARKOVS the three specialized ultrasound examinations for the assessment of fetal anatomy - in the first, second and third trimester. All examinations are performed in a comfortable environment with quality ultrasound equipment by highly qualified health professionals.


For more information about the possibility to perform the first trimester scan at MC MARKOVS you can contact your doctor or call at the registration desk.


Attention: Due to the small fetal size and the subsequent rapid development, the ultrasound evaluation of the fetal anatomy at 12-13+6 w.g. is usually repeated later in gestation.