Prenatal Screening For Birth Defects

 

First Trimester Prenatal Screening: Is It Right for You?

Pregnancy can be a time of hope and excitement, but also a time of anxiety and questions. It is natural for expectant moms and dads to wonder, “Will my baby be healthy? Will she develop normally?” Thankfully, most of the time, the answer is “yes!” Statistics show that 3%-5% of babies are born with significant birth defects, meaning that at least 95% are not. Some expectant parents prefer to wait until birth to learn the child’s health status. Others choose prenatal testing to detect certain conditions before birth, especially if they have a family history of a genetic problem .

OB-Gyn practices in the New Hampshire are now offering first trimester prenatal screening for Down syndrome and other conditions. Previously, women who wanted this screening had to wait until the second trimester.

What is Down syndrome?
Down syndrome (DS) is one of the more common conditions caused by abnormal chromosomes, the structures that carry the DNA in each cell. The chances of having a baby with DS or other chromosomal abnormalities increases with age. People with DS are born with an extra copy of chromosome 21. You may be familiar with Chris Burke, an actor with DS from the television series “Life Goes On.”. People with DS have a characteristic facial appearance and mild to moderate mental retardation. They also often have heart defects and other medical complications.

What is first trimester screening?

A two-part test:

1. targeted ultrasound to measure the nuchal translucency (NT), a fluid-filled space at the back of the fetal neck.
2. a blood test to measure pregnancy-specific proteins found in the mother’s blood.
   By combining these measurements with the woman’s age and other factors, the lab calculates two numbers. One is for the chance of DS, the other for Trisomy 18 (T-18), a more rare but more serious condition.

If, for example, the screening shows a risk for DS of 1:200, that means that if 200 pregnant women with these same screening results were all in the same room, one of them would have a baby with DS. Another way to think of it is that 99.5% would not have a baby with Down syndrome. If the risk were 1:10, that would mean if ten women were in the room, one would have a baby with Down syndrome (90% would not.)

The testing lab sets a number at which someone is “screen positive” for DS. Being told you are “screen positive” does not mean your baby definitely will be born with DS. It just means your result is above the threshold. Diagnostic testing, usually CVS (chorionic villus sampling) or amniocentesis, is necessary if you want a definite answer regarding DS or other chromosomal conditions.

Prenatal screening cannot check for all, or even most, birth defects. There is currently no prenatal treatment for DS and related conditions.

Elliot Health System offers genetic counseling to help expectant parents understand these tests, and make the choices that are right for them. Please call Ann Jeffers-Brown at (603) 6630-8611 for more information.

 

 

Helpful Links

 

American Cancer Society's website: www.cancer.org and toll-free number, 1.800.ACS.2345, is staffed with Cancer Information Specialists 24 hours a day, 7 days a week.

Thousands of New Hampshire residents dial 1-800-ACS-2345 for comprehensive cancer information and services every year. The American Cancer Society’s toll-free number and our www.cancer.org Web site offer free cancer-related services, educational materials, information, and support, 24 hours a day, seven days a week.

• The American Cancer Society’s Road to Recovery program provided 2,500 rides to and from treatment for New Hampshire cancer patients in 2005.
• Hundreds of New Hampshire women undergoing cancer treatment attend Look Good…Feel Better workshops to learn how to deal with the appearance-related side effects of treatment. Many receive free wigs or turbans.
• Reach to Recovery®, a peer-to-peer breast cancer support program, is available throughout New Hampshire to people with breast cancer, especially those who have been newly diagnosed.
• I Can Cope, an educational program for cancer patients, their families, and caregivers, is also offered.

www.nsgc.org (National Society of Genetic Counselors) The National Society of Genetic Counselors website provides information about the genetic counseling profession, family history tools, upcoming conferences, and local genetic counseling services.

http://www.ashg.org/genetics/ashg/ashgmenu.htm (American Society of Human Genetics)

http://www.hhs.gov/ (U.S. Department of Health and Human Services)

http://medlineplus.gov (MedlinePlus and National Library of Medicine)

www.nlm.nih.gov/medlineplus/linking.html

http://www.brighamandwomens.org/feature_nov052.aspx (Brigham and Women’s Hospital National Family Health Initiative)

http://www.bio.brandeis.edu/gc01/ (Brandeis Genetic Counseling Program)

http://www.bumc.bu.edu/Dept/Content.aspx?DepartmentID=118&PageID=9006 (Boston University Genetic Counseling Training Program)

www.nergg.org (New England Regional Genetics Group)

www.geneticalliance.org (Genetic Alliance

www.facingourrisk.org (FORCE: Facing Our Risk of Cancer Empowered)

http://www.simmons.edu/shs/clinicalgenetics/ (Simmons Genetic Counseling Training)