Question
I am 22 weeks pregnant now, and the doctor recommended that I get a chromosome test at 20 weeks, but I didn’t go because I was traveling at the time. I’m not sure if I can still get tested at 21 weeks. So I want to ask if it’s still possible to get tested now, and if so, I’ll go now. Could someone with experience please give me an answer, thank you.
Answer
Down syndrome screening is a method that involves drawing a pregnant woman’s serum to detect the concentration of alpha-fetoprotein and human chrionic gonadotropin (HCG) hormone in the maternal serum, and combines the woman’s due date, age, weight, and gestational age at the time of blood draw to calculate the risk coefficient of giving birth to a Down syndrome child. The purpose of Down syndrome screening is to detect Down syndrome early. Humans have 23 pairs of chromosomes, totaling 46. If there is a problem with the 21st pair of chromosomes, the baby may miscarry or be born prematurely. If they survive, their intelligence may be lower than that of children of the same age. Therefore, once diagnosed, doctors usually recommend that pregnant women consider selective abortion, but the final decision is ultimately up to the pregnant woman herself. When facing high-risk Down syndrome or advanced maternal age, amniocentesis becomes a means to exclude abnormalities. The procedure involves applying antiseptic iodine solution to the abdomen, and the doctor inserts a needle into the amniotic cavity while guided by ultrasound, carefully avoiding the fetus. There may be a slight pain when the needle just pierces the skin, but it is not as painful as drawing blood. Collecting 28 grams of amniotic fluid takes only one minute, and the mother’s body will immediately replenish the lost amniotic fluid. In the laboratory, fetal cells are isolated from the amniotic fluid for chromosomal karyotype analysis, which can ultimately confirm whether the fetus has chromosomal abnormalities.
