- MEDICINE ATHENS MED4WOMAN ATHENS
- MEDICINE VOLOS MED4WOMAN VOLOS
- 2103390838
- 2421022988
Obstetrician Gynaecologist
Doctor of Medicine, University of Athens Medical School
Panagiotis Polyzos, Gynaecologist Obstetrician, is active at the Institute of Life - IVF Unit of Iaso Maternity Hospital.
Το Second-Trimester Anatomy Scan is performed between the 20thfrom and 24thfrom 24th week of pregnancy, with the optimal gestational age being 21η - 22η 22 weeks. It is considered the most important examination of the second trimester. Its purpose is to rule out major anatomical abnormalities and to assess a range of specific markers that are more frequently associated with chromosomal abnormalities in the fetus. Measurements are taken to estimate fetal weight and evaluate fetal growth, and the fetal anatomy is examined in detail to detect any congenital anomalies.
During the Second-Trimester Anatomy Scan, the following structures are thoroughly evaluated: the skull, brain, face, spine, chest, lungs, heart, abdomen, intestines, kidneys, bladder, and both upper and lower limbs. The position of the placenta is also determined, and the amount of amniotic fluid is assessed.
In addition, nine (9) specific markers for possible chromosomal abnormalities are examined. The findings are correlated with the final results from the nuchal translucency ultrasound.
This scan allows for the detection of potential fetal anatomical abnormalities, evaluation of minor anomalies or markers indicating chromosomal disorders, and assessment of the risk for preterm birth, preeclampsia, and fetal growth restriction.
The diagnostic value of this examination for detecting major congenital abnormalities is approximately 75% worldwide. This means that a normal Second-Trimester Anatomy Scan — no matter how thorough and complete it may be — can significantly reassure the couple and the treating physician, but it cannot rule out all abnormalities, nor guarantee the birth of a completely healthy baby.
The results of the examination will be discussed with a Maternal–Fetal Medicine Specialist, who will clarify any questions you may have and provide further information and guidance for managing any potential issues.
It is the most important and detailed ultrasound examination within the framework of prenatal care; therefore, the Second-Trimester Detailed Anatomy Scan is recommended for all pregnant women.
The fetal anatomy is assessed system-by-system, covering all vital organs. A detailed examination is performed of:
The normal bone density and shape of the skull, the brain hemispheres, the ventricles and cerebellum, the lenses of the eyes, the nose, the upper and lower jaw, the tongue, the pharynx, the lips and the facial profile, the curvature, shape and bone density of the spine and pelvic bones, the neck, the chest and lungs, the anatomy of the heart, the abdominal wall, the umbilical cord insertion site, the gastrointestinal tract, the shape and position of the stomach, the kidneys, the urinary bladder and the genital organs, the shape and bone density of the humerus, radius, ulna, femur, tibia and fibula, the palms, the fingers and the feet.
During the examination, advanced imaging techniquesmay be used to improve the detection capability for potential anatomical defects. Thus, among others, MRI-like scanning of the fetal brain and multiplanar imaging of the heart and the major thoracic vessels are performed using three-dimensional imaging (3D-TUI). Nevertheless, it should be noted that a normal ultrasound scan cannot fully exclude the presence of anatomical abnormalities, but the more detailed the evaluation, the lower the probability of their existence. The examination is performed using specific standardized ultrasound planes, as defined by the respective protocols of the Fetal Medicine Foundation–FMF and ISUOG, which have been proven to demonstrate the highest sensitivity in detecting potential fetal abnormalities.
During the Second-Trimester Detailed Anatomy Scan, markers for chromosomal abnormalities are assessed.
The most important among them are:
The presence of one or more markers does not usually constitute a problem on its own, but it significantly increases the likelihood that the fetus may have a chromosomal abnormality. It is worth noting that the Second-Trimester Detailed Anatomy Scan has low sensitivity in detecting chromosomal abnormalities, as 40% of children with Down syndrome appear normal during this examination.
Chromosomal abnormalities are primarily detected during the 11–14 week scan (nuchal translucency) with a sensitivity of 93–95%. The various ultrasound markers of the second trimester are considered “soft markers” and, if present, are used to recalculate the probability of chromosomal abnormalities previously established in the first trimester. The cervix and blood flow in the uterine arteries are also evaluated. In this way, the individualized risk of preterm birth, preeclampsia, and fetal growth restriction is determined.
If structural abnormalities are identified during the detailed fetal anatomical evaluation, the significance of the findings will be discussed, and the prospective parents will have the opportunity to receive additional counseling and guidance. Further diagnostic tests, including NIPD test and invasive tests such as amniocentesis , may also be performed.
A moderately full bladder is sufficient for performing the transabdominal ultrasound, while it is advisable to have eaten something light before your scheduled appointment.
The Second-Trimester Anatomy Scan is recommended for ALL pregnancies, regardless of maternal age. Additional indications include a previous pregnancy with an anatomical or genetic abnormality, suspicion of a fetal anomaly in the current pregnancy, known fetal growth disorder, or any other potential complication that may affect the fetus (e.g., congenital infection). In such indications, the evaluation of the fetus may require further assessment of the fetal anatomy or heart, compared to the standard second-trimester fetal examination.
It should be clarified that the only way today to diagnose or confidently exclude chromosomal abnormalities is through invasive prenatal procedures (amniocentesis or chorionic villus sampling), which are performed under specific indications or at the request of the mother. Therefore, although a normal Second-Trimester Detailed Anatomy Scan is reassuring, it does not guarantee the birth of a healthy baby.
