Trisomy 18

Everyone knows that human health depends very much on the set of chromosomes that are located in pairs in the structure of human DNA. But if there are more of them, for example 3, then this phenomenon is called "trisomy." Depending on which pair the unplanned increase occurred, the disease is also called. Most often this problem occurs in the 13th, 18th and 21st pair.

In this article, we will talk about trisomy 18, which is also called Edwards syndrome.

How to detect trisomy on chromosome 18?

To detect such a deviation in the development of the child at the gene level, like trisomy 18, can only be done by screening at 12-13 and 16-18 weeks (suppose the date is transferred to 1 week). It includes a biochemical blood test and ultrasound.

The risk of a child having a trisomy 18 in the child for a deviation less from the normal value of the free hormone b-hCG (human chorionic gonadotropin) is determined. For each week, the indicator is different. Therefore, to get the most truthful answer, you need to know exactly the period of your pregnancy. You can focus on the following standards:

In a few days after the test, you will get a result where it will be indicated, what is your probability of having a trisomy 18 and some other abnormalities in the fetus. They can be low, normal or elevated. But this is not a definitive diagnosis, since statistical probabilistic indices have been obtained.

At increased risk, you should consult a geneticist who will prescribe more thorough research to determine whether there are or are not deviations in the set of chromosomes.

Symptoms of trisomy 18

Due to the fact that screening is fee-based and often gives an erroneous result, not all pregnant women do it. Then the presence of Edwards syndrome in a child can be determined by some external signs:

1. Increased duration of pregnancy (42 weeks), during which low fetal activity and polyhydramnios were diagnosed.
2. At birth, the child has a small body weight (2-2.5 kg), a peculiar head shape (dolichocephalic), an irregular face structure (low forehead, narrow eye sockets and small mouth), and clenched fists and overlapping fingers.
3. Deformities of limbs and anomalies of internal organs (especially the heart) are observed.
4. Since children with trisomy 18 have severe physical development abnormalities, they live only for a short time (after 10 years only 10% of them remain).