In the second trimester of pregnancy, between weeks 18 and 22, all pregnant women undergo a routine ultrasound called the 20 week ultrasound or “the 20 o’clock echo” (in waiting rooms and cafeterias), although their A more accurate name would be to call it a 20-week morphological ultrasound, since it performs a detailed examination of the entire morphology of the baby.
In week 20 of pregnancy your baby measures around 16-20 centimeters, weighs about 350 grams and his organs are already in an advanced stage of development, which allows any abnormality to be diagnosed.
How it is performed?
It is a normal ultrasound , very similar to that of the first trimester, which is performed on the woman’s abdomen, while she is lying down. It is not necessary to perform it on an empty stomach, nor should it be drunk previously, as required by pelvic ultrasounds.
There are many parameters that are observed and depending on the position of the fetus, the amount of amniotic fluid, the morphology and the “mastery” with the ultrasound, the test can last between 15 minutes and half an hour .
Morphological ultrasound at 20 weeks
The 20-week ultrasound allows to confirm that the fetal growth is correct for its gestational age, to assess the heartbeat, the movements of the fetus, its morphology and to observe its internal organs.
It is checked, although not with 100 percent reliability, if there is any malformation for what is usually a more exhaustive and detailed examination of the baby’s organs. The level of amniotic fluid, the functioning of the placenta and the umbilical cord are also monitored.
It is very likely that in this ultrasound the sex of the baby can be known, as long as its position allows it.
Do you have any danger?
It is a simple, harmless and painless technique. It does not involve radiation or exposure, so it is a safe practice for both the pregnant woman and the baby.
What is it for?
As we have said before, this ultrasound will analyze the morphology of the baby, its environment (placenta and amniotic fluid), the heart and other internal organs, as well as the baby’s movements. All this to check that it is developing within normal parameters.
By having further development, possible fetal malformations can be identified. It is estimated that 88.3 percent can be detected in the case of major malformations of the nervous system, 84 percent for the renal ones, and 38 percent for those related to the heart and large blood vessels of the circulatory system .
For example, the probability of detecting spina bifida in this test is 88% and that of hydrocephalus 98%.
In case of detecting any anomaly, it should be studied and evaluated proposing, if necessary, the carrying out of more detailed studies.
All this almost certainly means that your gynecologist or the person who is performing the test at that time, is much quieter than normal and does not pay much attention to you, especially if he is not already too talkative.
This does not necessarily indicate that he has found something wrong, be patient and wait for him to finish so that he can comment in detail and more relaxed how the test went.
3D and 4D ultrasounds
Traditionally, a conventional 2D ultrasound is performed, but depending on the power of the ultrasound machine, 3D (three-dimensional) or so-called 4D (three-dimensional moving) ultrasound images could also be obtained.
The images are often combined, first making a more exhaustive analysis in 2D and later in 3D or 4D to be able to see the face.
In Babies and more | Pregnancy from week 1 to week 40: everything that happens from conception to birth
