Genetic counseling in obstetrics is a professional assessment of a person's or couple's risk factors based on their family history, medical history, and/or pregnancy history. The goal of genetic counseling is not only risk assessment, but also explanation of the cause and inheritance of a disorder, communicating the availability of testing, the prognosis, medical management, and treatment.
Families with a history of inherited diseases or birth defects often can benefit from genetic counseling. Sometimes the process can begin before pregnancy occurs. In other instances, genetic counselors work with physicians who specialize in human genetics to determine what tests are advisable for high-risk pregnant women and to interpret the results. Some genetically transmitted conditions, such as thalassemia,Tay-Sachs disease and sickle cell anemia, are more commonly found in people from certain geographic regions or particular ethnic groups, and specific screening procedures are recommended. Also, the counseling will help to identify pregnancies at risk for conditions such as Fragile X syndrome. Genetic counseling includes taking a detailed three generation family history, explaining pertinent genetic issues, offering the appropriate prenatal tests, and discussing the risks and benefits of the testing so that patients can make informed decisions. If a fetal abnormality is found on an ultrasound, you may be referred for genetic counseling as well.
First Trimester Screening of Chromosomal Abnormalities
To determine the risk of certain chromosomal abnormalities, a combination of an ultrasound examination and a blood test can be done between the 11th and 13th weeks of pregnancy. This test, called an ultrascreen, combines a standard first-trimester ultrasound with a specialized measurement called a nuchal translucency. The blood specimen is analyzed for two chemicals, free Beta-hCG (human chorionic gonadotropin) and PAPP-A (pregnancy-associated plasma protein-A), which are normally found in the blood of all pregnant women. The results of the nuchal translucency and the blood test, when considered with the mother’s age, give a specific estimated risk for Down’s syndrome and Trisomy 18.
Genetic counseling will help couples to make a choice on the type of prenatal testing.