Similar to you.. my NT was 3.5mm high risk, but NIPT low risk. Besides down syndrome, abnormal NT also has higher risks of other genetic conditions and physical structural defects, eg hole in heart. These cannot be detected on NIPT.
Was super worried as this is our first too.. Was advised to do amnio and fetal heart scan. Heart scan came back normal.
At first we were quite unwilling to risk it, but after much consideration we decided to do amnio for peace of mind. It depends on your personal preference at end of the day.
Praying all goes well for you, please take care 🙏🏻
Anonymous