Patient's question:
I am 22 weeks pregnant. The doctor asked me to have a chromosomal test at 20 weeks, but I went out for fun back then and didn't go. Now I'm wondering if I can still get the test done at 21 weeks. So, I'd like to ask if it's still possible to do the test now. If it is, I will go right away. Please give me an answer from someone with experience. Thank you.Doctor's answer:
Down syndrome screening is a method that involves drawing blood from a pregnant woman to detect the concentration of alpha-fetoprotein and human chorionic gonadotropin in her serum. By combining this with the pregnant woman's due date, age, weight, and gestational age at the time of blood collection, it calculates the risk coefficient of giving birth to a child with Down syndrome.Purpose of Down syndrome screening: To determine the chromosomal series of the fetus and identify any congenital abnormalities.
Screening time: 14-21 weeks of pregnancy
The purpose of Down syndrome screening is to detect the condition early. Humans have 23 pairs of chromosomes, totaling 46. If there is an issue with chromosome pair 21, the baby may either miscarry or be born prematurely. If the baby survives, their intelligence may be slightly lower than that of their peers of the same age. Therefore, if a diagnosis is confirmed, doctors typically recommend selective abortion, but the final decision remains with the pregnant woman. In cases of high risk for Down syndrome or when the mother is of advanced age, amniocentesis becomes the method for excluding abnormalities.
Procedure:
- The abdomen is cleaned with an antiseptic solution (usually iodine).
- A needle is inserted into the amniotic cavity, guided by ultrasound to carefully avoid the fetus.
- There may be a slight pain when the needle first pierces the skin, but it is not as painful as blood collection.
- Collecting 28 grams of amniotic fluid takes only about 1 minute, and the mother's body will replenish the lost fluid quickly.
In the laboratory, fetal cells are isolated from the amniotic fluid for karyotype analysis, which can definitively determine whether the fetus has chromosomal abnormalities.
Under normal circumstances, the procedure usually takes only a few minutes. After the surgery, the mother only needs to be observed in the hospital for 30 minutes to 1 hour before leaving on her own.
Many expectant mothers have concerns about amniocentesis, fearing harm to the fetus, premature birth, or late miscarriage. However, there is no need to worry too much. In well-established hospitals with advanced technology, this procedure is highly refined, and the risk of complications is extremely low.
Cost: Varies between 400-1000.