As the pregnancy went on, the blood test became more reliable.
That is believed to be due to the increased concentration of fetal DNA within the mother’s blood, Bianchi says.
By 20 weeks, the test was 99% accurate, she says.
The test is not routinely done by doctors in the U.S., Bianchi says.
Do you have higher hCG levels with a girl?
But one thing that doctors know for certain is that in the second and third trimesters, women having girls display higher levels of a hormone known as maternal serum HCG (MSHCG) than do women pregnant with boys. Now new research suggests that such hormonal differences appear less than three weeks after conception.
What is normal range for first trimester screening?
In the routine first trimester screening at 12 weeks and 2 days of gestation, the NT measurements of the first fetus was 3.4 mm (normal range for this age is 1.2-3.1 mm).
Photo in the article by “Mount Pleasant Granary”