The morphological ultrasound

There are many things that can be assessed through a morphological ultrasound on the state of the developing child.

The morphological ultrasound

In the central period of pregnancy, during the second trimester, around the  eighteenth  –  twentieth  week, a morphological ultrasound is done, one of the most important ultrasounds in pregnancy.

All pregnant women undergo this ultrasound examination routinely  in   order to check the growth and development of the baby and the regular evolution of the pregnancy.

How is it done? It’s simple: an ultrasound probe is passed over the skin of the lower abdomen with the aid of a gel: the latter only serves to improve contact between the probe and the skin.

The transvaginal ultrasound

Morphological ultrasound is a transabdominal ultrasound.

But sometimes you want to check the state of a low placenta, you want to check the length of the cervix or for other reasons, a transvaginal ultrasound is also necessary ,

This type of ultrasound is done by inserting a probe inside the vagina: it is an examination that generally creates less discomfort than a pap test, and therefore no type of anesthesia is required.

Why is this ultrasound needed?

The second trimester morphological ultrasound    is done in order to check that everything is going the right way as it allows you to have an accurate scan of the developing baby.

There are many aspects of pregnancy that your doctor will be able to evaluate

  1. The shape and structure of the baby’s head: Rare brain problems (such as microcephaly ) can be detected at this stage of pregnancy .
  2. The child’s face:  this is used to check that he does not have a cleft lip (if instead the problem concerns the palate, it is not possible to detect it since the inside of the mouth is not visible).
  3. The child’s spine:  both in length and in cross section, to make sure that all the bones are aligned, and that they are covered by skin.
  4. The abdominal wall:  to make sure it covers all the internal organs in the ventral part, the placenta, the umbilical cord, and the amniotic fluid.
  5. The heart:  the baby’s atria and ventricles should be the same size; the valves should open and close with each beat; in addition, the doctor will be able to check the main arteries and veins;
  6. The stomach:  the baby normally swallows part of the amniotic fluid in which it is immersed, which liquid manifests itself as a black bubble in the stomach;
  7. The kidneys:  the doctor may check that both kidneys are present, and that urine flows unimpeded into the bladder; if at the time of the examination the bladder is empty it is not a problem, because it will probably fill up during the examination itself since the child urinates about every half hour;
  8. Your arms, legs, hands, and feet:  Your doctor may check your toes and fingers, but won’t count them.

The placenta may be located in the anterior part of the uterine wall, or in the posterior part and closer to the fundus of the uterus (therefore the most cranial part). In the latter case, you may find the notation placenta fundica in the report.

The placenta will be described as low lying if it reaches or covers the neck of the uterus or cervix. In the latter case it will be necessary to carry out a new ultrasound in the third trimester to check its position, which will probably have changed as it moves away from the cervix.

It is possible, if desired, that the doctor can count the blood vessels (two arteries and one vein) in the umbilical cord. Finally, the doctor will check that the amniotic fluid is sufficient to allow free movement of the baby.

During the visit, the doctor will measure some parts of the child’s body, to understand how much he is growing. In particular he will measure,

  • the circumference of his head;
  • his abdominal circumference;
  • the femur.

The results of these measurements should correspond to the expected size of a fetus, in relation to the expected date of delivery, which date will have been determined during a previous ultrasound.

If, on the other hand, during the first ultrasound there were problems, this ultrasound will also be used to determine the date of delivery.

What anomalies can be detected

The doctor who performs the morphological ultrasound must check that a whole series of disorders do not exist, some of which could be serious to the point of threatening the very survival of the fetus, or less serious as they can then be treated after birth.

In this second case, knowing the situation in advance will help hospital staff manage the newborn in the best possible way at the time of delivery.

Some disorders are more difficult to detect than others. Some are only rarely recognized.

Most of the possible diseases that we will now indicate are very rare. However, here is the list of conditions, with the relative percentage of probability that the doctor can find them:

  • Anencephaly – 98%
  • Cleft Lip  – 75%
  • Abdominal wall defects and protrusion of bowel and liver – 80%
  • Short or missing limbs – 90%
  • Spina bifida – 90%
  • Kidney problems – 84%
  • Diaphragmatic hernia – 60%
  • Hydrocephalus – 60%
  • Edwards and Patau Syndrome – 95%
  • Heart problems (defects of the chambers, valves or vessels) – 50%

Some disorders, such as heart defects and intestinal blockages, may not be noticed until later in pregnancy. As mentioned, these conditions are usually very rare, and most newborns are born healthy.

When it highlights problems

Most problems that require a second morphological ultrasound are not serious. However, only 15% of ultrasounds are repeated for one reason or another.

The most common reason is that the doctor has not been able to see everything he was supposed to, perhaps because the baby was not positioned optimally, or because you are overweight, and therefore the ultrasound will probably be repeated in the 23rd  week .

If your doctor finds – or suspects – a problem, you will be notified immediately and likely set up a new appointment with a fetal medicine specialist.

If the doctor suspects that the fetus has a heart problem, you will be asked to go to a specialist in which a detailed ultrasound of the baby’s heart will be performed.

If the ultrasound reveals serious problems, support should always be provided to guide you through the options available.

Although serious problems are rare, many families are faced with the most difficult decision of all, whether or not to continue the pregnancy.

Other problems may require surgery or care after birth or even intrauterine surgery.

Either way, there will be a variety of people there to help you if these more serious issues are discovered.

Katherine Johnson, M.D., is a board-certified obstetrician-gynecologist with clinical expertise in general obstetrics and gynecology, family planning, women’s health, and gynecology.

She is affiliated with the Obstetrics and Gynecology division at an undisclosed healthcare institution and the online platform,

Leave a Reply

Your email address will not be published. Required fields are marked *