Patient's question:
I got married last year. Recently, I've been experiencing lower abdominal pain, especially during my period. I'm very worried about it affecting fertility, and I'm also extremely sensitive to cold and coldness. What is the purpose of measuring the thickness of the nuchal translucency in the fetus?Doctor's answer:
The so-called nuchal translucency refers to the thickness of the fluid accumulation in the subcutaneous tissue behind the fetal neck, which is reflected in the sonogram as an anechoic layer in the subcutaneous tissue behind the fetal neck. If its thickness increases, the likelihood of fetal abnormalities also increases. Since the changes in nuchal translucency are closely related to gestational age, strict regulations have been made regarding the gestational age for measuring nuchal translucency, specifically limiting the detection to the 10th to 14th week of pregnancy. After the 14th week of pregnancy, many cases of increased nuchal translucency can gradually subside. Only a small number of cases with extremely thick nuchal translucency or those that have formed a cervical cystic hygroma can still be observed as thickened in the sonogram, but the severity of the thickening change may be significantly reduced. In normal pregnancies during the 10th to 14th week, the thickness of the nuchal translucency slightly increases with gestational age. A rough and simple estimation method is that values <2.5 mm are considered normal, while values ≥2.5 mm are diagnosed as nuchal translucency thickening. When extreme thickening occurs, it can form a fetal cervical cystic hygroma.The degree of nuchal translucency thickening is closely related to fetal abnormalities. The more pronounced the thickening, the higher the chance of fetal abnormalities, and the more severe the abnormalities. Some studies have found that when the nuchal translucency thickening is 3 mm, 90% are normal fetuses, while 10% are abnormal fetuses; whereas when the nuchal translucency thickening reaches 6 mm, 90% are abnormal fetuses. Due to the close relationship between nuchal translucency thickening and fetal abnormalities, a detailed ultrasound examination is very important. During the 10th to 14th week of pregnancy, many structures cannot yet be determined, but if transvaginal high-frequency ultrasound is used, some malformations can still be detected, such as anencephaly, encephalocele, brain herniation, holoprosencephaly, spina bifida, severe cardiac malformations, certain diaphragmatic hernias, omphalocele (after the 12th week of pregnancy), gastroschisis, polycystic kidney disease, fetal-type polycystic kidney disease, renal agenesis, megaureter, body stalk anomaly, lethal skeletal malformations, and some skeletal muscle abnormalities, etc. For pregnancies in the 10th to 14th week where, in addition to thickening of the translucency, no other obvious abnormal ultrasound findings are present, it is still necessary to re-examine the ultrasound after several weeks, because most fetal malformations can only be screened and diagnosed after the 17th to 20th week.