Is NT 3.6mm severe?
Nov 11, 2025
Source: Cainiu Health
Dr. Zhang Lu
Introduction
Under normal circumstances, an NT measurement of 3.6 mm exceeds the normal reference range, indicating an increased risk of chromosomal abnormalities or structural malformations, and further evaluation is required. If subsequent tests such as non-invasive DNA testing or amniocentesis show no abnormalities and ultrasound reveals no fetal structural issues, the risk may be reduced and is not considered severe. If concerned, it is recommended to seek medical advice early. A detailed analysis is as follows:
Generally, an NT measurement of 3.6 mm exceeds the normal reference range, indicating an increased risk of chromosomal abnormalities or structural malformations, and further evaluation is recommended. If subsequent tests such as non-invasive DNA testing or amniocentesis show no abnormalities, and ultrasound reveals no fetal structural issues, the risk is significantly reduced and the condition is not considered serious. If concerned, it's advisable to consult a healthcare provider early. Detailed analysis is as follows:
If the NT is 3.6 mm and subsequent non-invasive DNA testing indicates chromosomal abnormalities (such as trisomy 21), or amniocentesis confirms a chromosomal abnormality, or ultrasound detects structural malformations in the fetal heart, brain, or other organs, these findings indicate a clear risk of abnormalities. This situation requires close attention and management under a doctor’s guidance, and is considered relatively serious.
If the NT is 3.6 mm but non-invasive DNA testing results are normal, amniocentesis shows no chromosomal issues, and multiple ultrasounds confirm normal fetal structural development, the slightly elevated NT may represent a transient physiological phenomenon without significant health risks. In such cases, the condition is not considered serious, although regular prenatal check-ups are still necessary to monitor fetal development.
If any abnormalities are detected, it is important to communicate fully with your doctor and follow professional recommendations to determine the appropriate course of action, ensuring the safety of both mother and baby.
