2nd Trimester Scan
In the ultrasound of the 2nd trimester of pregnancy, a thorough check of the fetal anatomy is performed to check if the fetus develops normally and to detect any abnormalities of the fetus. The examination is done transabdominally. Fetal growth and anatomy is monitored and all vital organs are checked. The doctor explains the image on the screen and ultrasound findings in detail.
- Skull: the shape and normal bone density of the skull is checked.
- Brain: the architectural structure of the brain, the hemispheres, the ventricles and the cerebellum
- Face: eye lenses, nose and nostrils, upper jaw and hard palate, mandible, tongue, pharynx, lips, ears and fetal profile
- Spinal column: normal bone density and shape of the spine and pelvic bones.
- Neck-chest: neck, chest and lungs
- Heart: the four cavities of the heart, the aortic arch, the aortic and pulmonary outflows, the junction of aortic arch with the ductus arteriosus, the right subclavian artery, the interventricular diaphragm, the pulmonary veins, normal functioning or deficiency of the tricuspid and mitral valve.
- Abdomen: the abdominal wall, the stomach, the intestine of the fetus, the gall bladder, the liver and the liver vein
- Urinary system: the kidneys, the bladder and the genitals
- Bones: the bone density and shape of the bones of the humerus, the radius, the ulna, the femur, the tibia, the fibula
- Limps: palms and fingers, feet and toes
In addition, in the ultrasound of the 2nd trimester, the chance of the fetus having the Down syndrome is redefined based on the presence or absence of specific ultrasound findings (minor indicators for chromosomal abnormalities) which are:
- The thickness of the nuchal fold.
- Short femur.
- Echogenic focus (echogenic area in the heart).
- Hyperechogenic bowel (more intense reflection in bowel imaging with ultrasound).
- Aberrant right subclavian artery
- Absent or hypoplastic nasal bone
It should be noted that the 2nd trimester ultrasound has a low sensitivity to the detection of chromosomal abnormalities. For example, 40% of children with Down syndrome appear normal during this examination.
In case a minor ultrasound indicator is detected, the chance of a chromosomal abnormality is redefined based on the risk identified in the 1st trimester. If an indicator is detected, the chance of a chromosomal abnormality is enhanced. It does not necessarily mean however that the fetus suffers from a chromosomal abnormality. The same applies for the reverse. That is, if no anomaly is detected, it does not mean that the chances of anomalies are nullified, but suspicions of possible anomalies are reduced. The only way to diagnose a chromosomal abnormality or a genetic syndrome in the 2nd trimester of pregnancy is by performing amniocentesis (with a 1% risk of a miscarriage)
This ultrasound check is performed between the 18th and 24th week of pregnancy, but usually between the 20th and the 22nd week. The reason for choosing this specific time period is because the fetus has developed adequately and examination is possible since the fetus can take the appropriate place for the examination and does not exceed the 24th weeks, which is the legal limit allowed for the termination of a pregnancy in case a serious anomaly is diagnosed.
The 2nd level ultrasound is performed by individuals who are qualified and certified to perform this specific examination and participate in a continuous annual check of their results for the renewal of their license. (Unlike the 1st trimester ultrasound that can be performed by each obstetrician or radiologist without any specialization and similar experience.)
At the following site people can be informed of the certified physicians in Cyprus who are certified by the FMF (Fetal Medicine Foundation) to perform this specific examination. (https://fetalmedicine.org/lists/map/certified/fetal-abnormalities)
As for the effectiveness of the 2nd trimester ultrasound, however detailed it might be, it cannot rule out all the anomalies and guarantee the birth of a normal child. The reason is that 20-30% of the abnormalities that exist cannot be diagnosed during the examination either because they are not seen in the 2nd trimester ultrasound and these abnormalities could appear on an ultrasound later in the 2nd or 3rd trimester or not at all, or because the diagnostic potentials of the examination are limited by problems of a technical nature (eg limited display due to the increased body weight of the pregnant patient) etc. Thus, on the 2nd trimester analytical ultrasound, an average of 70% of the serious and 45% of the mild anatomical abnormalities of the fetus can be detected.
Furthermore, during the examination of the 2nd trimester, if the woman wishes, the cervix and blood flow in the uterine arteries can also be examined and define the risk of premature labor due to cervical insufficiency and preeclampsia and fetal growth restriction due to poor placental perfusion. This examination is performed transvaginally but its duration is very short (usually 2-3 minutes).
At the end of the test, each patient will receive a report of what has been tested, as well as 2D, 3D and 4D pictures on DVD.