Who Gets the Test?
What the Test Does
How the Test Is Done
Using ultrasound to see an image of your twins, the doctor will guide a thin needle through your womb and into a tiny blood vessel in your babies or in their umbilical cords. Your doctor will get a tiny sample of each of your babies' blood. You may feel some pressure or cramping. Then a lab will test the samples.
The procedure has different names depending on how your doctor gets the blood. When the doctor takes the blood from the umbilical cords, it's called percutaneous umbilical cord blood sampling (PUBS.)
What to Know About Test Results
Test results usually come back within three days. If they show that one (or both) of your babies has a problem, you will meet with your doctor or a counselor to discuss your options. If either of your babies has an infection or anemia, treatment can help. FBS is accurate at diagnosing some birth defects. However, it doesn't show how severe they are.
How Often the Test Is Done During Pregnancy
If you need fetal blood sampling, you would probably get it at about 17 to 18 weeks. This timing varies depending on the reason for the testing such as anemia or infection. It could also be done at any time during your pregnancy and possibly several times.
Other Names for This Test
Cordocentesis, percutaneous umbilical blood sampling, umbilical vein sampling, funiculocentesis, fetal intrahepatic blood sampling, fetal cardiocentesis
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