I thought the NIPT test tested for trisomy 13, 18, and 21 as well as a sex chromosome abnormalities. Spina bifida would be tested for with genetic testing. I could be wrong, just my understanding.

They arent the same test. The NIPT doesnt test for spina bifida. They have the 16 week quad screening that tests for neural tube defects such as spina bifida. Its called the AFP or the AFT.

The NIPT would show results for spina bifida but as far as I know the test isn't a predictor of miscarriage. It just shows any genetic abnormalities your baby may have.

And yes you can still miscarry after the nipt because sometimes things just happen that cant be predicted or tested for

Nipt shows any abnormalities in the genes that can be used as a predictor for things such as down syndrome.