NT: Normal range
Aug 24, 2022
Source: Cainiu Health
Dr. Chen Zhe
Introduction
The nuchal translucency (NT) measurement should be less than 2.5–3 mm; values exceeding this range are considered high-risk. Between 11 weeks and 13 weeks + 6 days of gestation, all pregnant women should routinely undergo ultrasound examination to measure the NT—the thickness of the fetal nuchal translucency—with 2.5–3 mm serving as the cutoff value. Additional targeted ultrasound screening is recommended during the second trimester. If severe fetal structural anomalies are detected, termination of pregnancy may be indicated during the second trimester.
As is widely known, Nuchal Translucency (NT) screening is a critically important prenatal test used to help assess the risk of congenital abnormalities in the fetus.
Normal NT Range
A normal NT measurement is less than 2.5–3 mm. Measurements exceeding this threshold are considered high-risk. Between 11 weeks and 13 weeks + 6 days of gestation, all pregnant women should routinely undergo ultrasound examination to measure the fetal nuchal translucency—the thickness of the fluid-filled space at the back of the fetal neck. An NT value greater than 2.5–3 mm is associated with an increased risk of chromosomal abnormalities (e.g., trisomy 21, 18, or 13) and structural fetal anomalies. In such cases, definitive diagnosis typically requires amniocentesis during the second trimester. If chromosomal abnormalities are confirmed via amniocentesis, termination of pregnancy during the second trimester may be recommended. Additionally, enhanced ultrasound screening should be performed in the second trimester; if severe structural anomalies are detected, termination may also be indicated.
The optimal window for NT screening is between 11 weeks and 13 weeks + 6 days of gestation. Pregnant women must schedule this ultrasound examination within this timeframe and follow up with appropriate clinical management based on results. The NT measurement reflects early embryonic development. If first- or second-trimester serum screening (e.g., combined or quadruple test) yields abnormal results, further diagnostic evaluation—including NT assessment—is strongly advised.
Pregnant women should engage in appropriate physical activity during daily life to strengthen their constitution and prevent illness. Diet should be light yet nutritionally balanced to ensure adequate intake of essential nutrients. We hope this information is helpful. Wishing you good health and happiness!
