Combining an NT scan with a blood test gives a more accurate result.
The blood test measures the levels of the hormone, free beta-h CG, and the protein, PAPP-A.
It shouldn't hurt, though you may feel some pressure as the sonographer presses the transducer into your skin to get a good view.The baby with an NT of 2.9mm is also within the limit of normal range. Nine out of 10 babies with a measurement between 2.5mm and 3.5mm will not have Down's syndrome As the NT increases, so does the chance of Down's syndrome and other chromosomal abnormalities. The baby with an NT of 6mm has a high chance of Down's syndrome, as well as other chromosomal abnormalities and heart problems. It's rare for babies have as much fluid as this. She'll then measure the width of the nuchal fluid at the back of your baby's neck.