Second Trimester Tests During Pregnancy
Cordocentesis: This test, also known as fetal blood sampling (FBS) or percutaneous umbilical cord sampling, collects fetal blood directly from the umbilical cord or fetus. This test can be used to measure anemia and blood oxygen levels and to screen for maternal Rh antibodies. Cordocentesis can be done as early as the 17th week of pregnancy.
Fetal Doppler ultrasound: A Doppler ultrasound test uses sound waves to evaluate blood as it flows through a blood vessel. Fetal Doppler ultrasound can determine if blood flow to the placenta and fetus is normal.
Fetoscopy: Fetoscopy allows a doctor to see the fetus through a thin, flexible instrument called a fetoscope. Fetoscopy can detect some diseases or defects that cannot be found by other tests, such as amniocentesis, ultrasound, or chorionic villus sampling. Because fetoscopy carries significant risks for the mother and fetus, it is an uncommon procedure that is only recommended if there is a much higher-than-normal chance that the baby will have an abnormality.