In the field of genetic counseling, there is a variety of different specialties with one of the largest being prenatal genetic counseling. This specialty exists to assist parents that have a history of a genetic condition, difficulties with pregnancy or other risk factors that may affect family planning. The genetic counselor is specially trained to help assess risk and determine the best available options for families.
Prenatal genetic counseling is not necessary for all people who are planning on having children. Someone may be referred to a genetic counselor based on family history of a genetic condition or birth defect. If a couple has a history of multiple miscarriages or trouble getting pregnant, they may be referred to a prenatal genetic counselor to identify potential genetic explanations. Other reasons to a visit a prenatal genetic counselor include an unusual ultrasound, increased age of the mother or association with an ethnic group that has a greater chance of having a genetic condition. After an initial conversation and introduction, the genetic counselor will always begin the appointment with a full review of family history in order to help the counselor assess the need for genetic testing.
Following discussion of family history, the genetic counselor will provide information and facilitate discussions of genetic testing and what the potential results could indicate. The couple will then need to decide what options are best for their needs. Some common tests that are offered include amniocentesis and chorionic villus sampling (CVS).
Amniocentesis is a procedure that tests the amniotic fluid around the baby for fetal cells that provide information about genetic makeup. This procedure is invasive and has associated risks such as a increased risk for miscarriage, but it can provide important information that may help better manage the pregnancy or influence decisions to continue the pregnancy. Amniocentesis can detect chromosome abnormalities such as trisomy 21, a genetic condition where the fetus has three copies of chromosome 21 instead of the usual matched pair. Also known as Down syndrome, trisomy 21 is one of the most common genetic birth defects. Amniocentesis can also give information on genetic mutations that cause diseases such as cystic fibrosis, a recessive mutation that occurs when both parents pass on a mutated gene.
Chorionic villus sampling is another common test offered in prenatal genetic counseling in which the chorionic villi, part of the placental tissue, are removed for genetic testing. This procedure also has associated risks but can determine conditions such as trisomy 21 or cystic fibrosis. CVS can be utilized between weeks 11 and 14 of pregnancy, earlier than most prenatal diagnostic methods, including amniocentesis which cannot be utilized until week 15 of pregnancy. However, CVS cannot detect all the same conditions as amniocentesis.
One of the most important roles of the prenatal genetic counselor is to provide support for the family while they are making decisions about genetic testing. The genetic counselor helps the family process emotions and stress that may be triggered by problems with pregnancy or nerves about the pending results of their testing. No matter what the scenario is, prenatal genetic counselors provide information and guidance throughout the entire genetic testing process and are a constant source for support and information to families whenever necessary.