Why sometimes the prenatal examination can't find out the fetal malformation?

Giving birth to a healthy baby is the wish of all parents, but there is still a very small chance of giving birth to a deformed baby. Many people are surprised, why do they still give birth to a deformed baby even though they have regular prenatal checkups? Let's take a look at the following article to find out!

Why sometimes the prenatal examination does not detect malformation in the baby

Current prenatal examinations cannot rule out all fetal malformations

Prenatal examinations use appropriate medical technology to diagnose the health of the fetus, but many current prenatal examinations can only conduct structural examinations, such as determining whether the fetus's body is abnormally developed. However, many deformities manifest as functional problems, such as cerebral palsy, which is a functional brain disorder, and current prenatal examination technology is unable to detect such functional problems.

What fetal abnormalities can't be detected?

1. Vision: Although the vision of the fetus has developed at 10 weeks of gestation and the pupil of the fetus has light-sensitive function at 24 weeks of gestation, it is dark inside the womb and there is no light stimulation at all. Even if you use a flashlight for prenatal education, you cannot diagnose whether the fetus's vision is normal.

2. Hydrocephalus: Hydrocephalus is a disease caused by excessive cerebrospinal fluid. The fetus with hydrocephalus will have an enlarged head circumference and a prominent fontanelle. This phenomenon usually occurs gradually in the late pregnancy, and it is difficult to detect it during prenatal examinations. It can only be discovered slowly after the baby is born.

3. Hearing: The fetus’ vision has developed at 5-6 months of pregnancy, and scientific prenatal education can be given to the fetus at this time. However, even so, there is no instrument that can confirm whether the fetus’ hearing is normal. We can only wait until after birth to do a hearing test.

4. Gastrointestinal obstruction: A small number of fetuses will experience this before 24 weeks of pregnancy, but the chance of detection is very low and it is difficult to detect during pregnancy.

5. Abnormalities of the extremities (fingers and toes): These are small deformities. During the fetal period, babies often curl up in their mother's belly, with their hands in a clenched fist, so it is difficult to find out if their fingers are abnormal; their feet are also often hidden, so it is difficult to see the specific condition of their toes.

6. Dwarfism: Dwarfism is usually discovered after the baby is born, as the baby grows and develops. And many babies with dwarfism are about the same height as normal babies when they are born.

7. Congenital metabolic abnormalities: Metabolic abnormalities usually develop gradually after the baby is born and starts eating.

8. Congenital heart disease: The atrial septum and arteriovenous ductus of the heart will gradually close after the baby is born, and it is impossible to detect it in time during pregnancy.

It can be seen that although prenatal examination is an effective means of fetal malformation exclusion, the current medical technology is still limited, and many malformations cannot be detected through prenatal examinations. At present, the main malformations that cannot be detected include fetal hearing, vision, dwarfism, intellectual disability, congenital metabolic defects, gastrointestinal obstruction, etc.

What is fetal malformation?

Fetal malformation refers to structural or chromosomal abnormalities that occur in the fetus in utero. It is a type of birth defect and the main cause of perinatal death. There are many types of fetal malformations. Some problems are relatively minor, such as a baby with a slight cleft lip, an extra finger, or a missing finger. Although these problems are unsightly, they will not affect the health of the baby. Some problems are relatively major, such as a baby's heart malformation or spina bifida, which seriously endanger the baby's health. Some are chromosomal abnormalities, such as Down syndrome, etc.

The most important thing is that pregnant women cannot feel fetal malformations and can only check them through prenatal checkups, but prenatal checkups cannot detect 100% of all malformations!

Related News

In order to ensure good birth and upbringing, pregnant women need to undergo multiple prenatal examinations during pregnancy, and the time and items of each prenatal examination are clearly defined. However, due to the limitations of medical technology, many prenatal examination items cannot guarantee 100% accuracy. For example, screening for Down syndrome usually involves NT examination and Down syndrome blood screening during prenatal examinations. If there is a high risk, non-invasive DNA and amniocentesis are required. After a complex screening process, the incidence of Down syndrome is still as high as 1/800-1/600.