Prenatal Genetic Screening

the pros and cons

What is Prenatal Gentic Screening?

Prenatal genetic testing refers to tests that are done during pregnancy to either screen for or diagnose a birth effect. The goal is to provide expectant parents with information to make informed choices and decisions.

Pros of Prenatal Genetic Screening

These tests Assists providers in providing the best care and management to your pregnancy. Screening tests- Screening test does not diagnose birth effect, they only determine if a fetus is at high or low risk for a specific condition. Examples of Screening-- First Trimester Screening (nuchal translucency), Cystic Fibrosis Carrier Screening and Modified Sequential Screening. First Trimester Screening is a combination of a blood test and ultrasound examination to help identify babies who may have Down Syndrome, Trisomy 18 or Trisomy 21. Cystic Fibrosis Carrier Screening is a blood test is used to tell women and men if they are carriers for Cystic Fibrosis. Modified Sequential Screening is a test that is a follow up to the First Trimester Screening (Ultra-Screen). It may be recommended to some patients, in order to provide more information to those women that are considered higher risk on the first trimester screening.

  • Approximately 85 out of every 100 babies affected by the abnormalities addressed by the screen will be identified.

  • Approximately 5% of all normal pregnancies will receive a positive result or an abnormal level.

  • A positive test means you have a 1/100 to 1/300 chance of experiencing one of the abnormalities.

further testing/screening allows decisions:
  • Pursue potential interventions that may exist (fetal surgery for spina bifida)

  • Begin planning for a child with special needs

  • Start addressing anticipated lifestyle changes

  • Identify support groups and resources

  • Make a decision about carrying the child to term

Cons of Prenatal Genetic Screening

Whether or not a woman decides to undergo genetic screening is her own choice, as positive results could produce anxiety and conflicting emotions. Those against genetic testing feel that the biggest disadvantage of prenatal testing is the tremendous psychological pressure imposed on the parents. They are in a constant anxiety about the possible results. They tend to get confused about the condition as in the case where a baby is known to carry a mutation, but sometimes the parents may not realize that this does not mean that the baby will contract the genetic disorder too. This point also questions the accuracy of the results. Prenatal testing is very expensive and thereby cannot be attempted by people with meager means. Further only a handful of insurance companies are ready to cover the expenses of these tests. This leaves couples with limited or no choice at all.


Prenatal screening tests do not guarantee a normal pregnancy or baby. Birth defects can happen at any point during the pregnancy, so the test may not show the disease. Birth defects occur in 1 in every 33 babies born in the United States. 5-20% of results will be wrong. Results will not be available for 15-22 weeks after second blood draw, so mothers may be anxious for results. Even a low-risk assessment still could mean a low risk of abnormalities.The test carries a small risk of losing the baby because of the sample of fluid around the fetus. So while this test can be helpful, there are to many risks to be concerned about.