Final answer:
Cordocentesis is a diagnostic procedure used to test for fetal abnormalities, including genetic disorders, by obtaining a blood sample from the umbilical cord. Genetic counselors assist by estimating genetic risks and helping interpret test results. Prenatal genetic diagnosis is an advancement that screens embryos for defects prior to implantation.
Step-by-step explanation:
When a genetic or metabolic defect is suspected in a fetus, a procedure known as cordocentesis, also referred to as percutaneous umbilical blood sampling (PUBS), may be performed. This procedure involves taking a blood sample from the umbilical cord to test for fetal abnormalities, including genetic disorders and infections. It is generally reserved for situations where the information cannot be obtained through less invasive tests such as amniocentesis or chorionic villus sampling (CVS).
Genetic counselors play an important role in this process, guiding prospective parents through the complex landscape of prenatal testing. They offer insights into genetic risks based on family history, help interpret test results, and support families with the emotional aspects of genetic diagnosis. Furthermore, prenatal genetic diagnosis (PGD) has emerged as a method to screen embryos for genetic defects as part of the in vitro fertilization process before implanting them into the mother's uterus.