Premorphological: what is it and when is it useful?

Fonte: shutterstock


The morphological ultrasound is always of great importance and is a source of enthusiasm and emotion for future parents: with this important echography It is possible to study in detail the skeletal and organ development of the fetus, identify any malformations, date the pregnancy more precisely and also discover, if we are lucky, the sex of the baby. But there is also another type of morphology, called premorphological, which is carried out before the traditional one. Let's see when it is indicated and what it is for.

In this article

  • Useful info
  • When you do
  • Values
  • Differences with the morphological

Useful info

When can a pre-morphological ultrasound be useful? This investigation is useful in cases such as high malformative risk (e.g. a previously born child with anomaly) to make a early evaluation of fetal anatomy, which can serve to anticipate the timing of the diagnosis. This allows the couple to deepen the diagnostic picture with any genetic tests or amniocentesis, which always require more or less long times.

La premorphological it can therefore be useful in the following cases:

  • when future mothers do not want to have an amniocentesis and still want to have a more defined picture of the situation;
  • they did the combined test and the result is unclear: that is, neither too high to justify the use of amniocentesis, nor too low to be safe;
  • have had previous pregnancies with malformations and anomalies, especially heart defects.
Read also: The ultrasound scans to do in pregnancy

When you do

La premorphological it is generally done between the 15 and the 18 weeks: this is a transabdominal ultrasound that can help identify any fetal abnormalities before the 20th week of gestation. The exam is considered, to date, only one screening methods and not an early diagnostic test. This is because in this gestational period the fetal structures are not yet completed, the baby's anatomy will change again and some pathologies will not necessarily already be visible.

How premorphological ultrasound takes place

The ultrasound it is an examination of the whole harmless to mother and baby: ultrasounds use sound waves, not radiation as X-rays do. Generally at this stage of pregnancy it is done transabdominally using, therefore, a probe that is passed on the abdomen of the expectant mother after having applied a special gel. A full bladder is recommended for better definition.


What can this ultrasound show us?

  • Fetal heartbeat and assessment of blood flow across the placenta;
  • Detailed measurements and examination of the growing child;
  • Detection of fetal structural anomalies;
  • The absence of risks for vaginal delivery (Vasa Praevia);
  • Accurate placement of the placenta in the uterus;
  • Volume control of amniotic fluid;
  • Examination of the pelvic structures of the mother;
  • Length of the cervix.

In principle, therefore, this exam includes:

  1. structural analysis of the fetus
  2. biometrics to measure the various fetal parts, such as cranial parameters, abdominal circumference, long bones
  3. search for "soft markers", which are indicators of chromosomopathy, and therefore allows to recalculate the risk for chromosomopathies.

Ultrasound of the fetus: the images month after month

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What happens if the ultrasounds become author's? The result is the following: nine wonderful images documenting the development of the fetus in the mother's womb month by month ....

Differences with the morphological

Lpremorphological ultrasound does not replace the morphological one, which is done between 21 and 22 weeks and is a diagnostic test. The premorphology does not allow, in this gestational period, to highlight any malconformation anomalies characterized by defects still too small to see, such as structural pathologies of the lips, brain or heart). Furthermore, it cannot identify pathologies that will become visible only later, such as thehydrocephalus

Having said that, therefore, premorphological ultrasound is essentially a evaluate the suspicion of any pathologies and anomalies which will serve the operator later to make a more aware and careful study of these aspects during the morphological ultrasound, and to eventually start a diagnostic process with more in-depth and long examinations and tests.


  • Early fetal morphological evaluation (11-13 + 6 weeks) accomplished exclusively by transabdominal imaging and following routine midtrimester fetal ultrasound scan recommendations. Since when can it be performed?

  • pregnancy ultrasound scans
  • prenatal diagnostic tests
  • first trimester ultrasound
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