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Screening tests offered for defects For more information on  the MUSC Prenatal Wellness Center, visit the Wellness Wednesday booth from 10 a.m. to 1 p.m. Sept. 6 in the Children’s Hospital lobby.   Although most babies are born healthy, the risk of producing a child with a birth defect concerns many parents. Screening tests are offered to all women during pregnancy to determine risks for certain types of birth defects, such as open neural tube defects and Down syndrome.   Approximately 5 percent of those undergoing screening are determined to be at increased risk and further testing can be performed to achieve a definitive diagnosis. Two screening tests are available at the MUSC Prenatal Wellness Center. The quad screen is performed at 15-21 weeks gestation. The test measures the levels of four substances in the maternal blood and uses them to calculate risks for Down syndrome, Trisomy 18 (a rare but more severe chromosomal abnormality), and open neural tube defects.   A newer screen is performed in the first trimester at 11-13 weeks gestation and combines an ultrasound measurement of the back of the baby’s neck with two substances from maternal blood to calculate the risk for Down syndrome and Trisomy 18. Both the first trimester and second trimester tests are screening tests and calculate risk only. Therefore, normal results decrease the risk for abnormality and abnormal results increase the risk that the baby is abnormal.   Diagnostic tests for chromosomal abnormalities in pregnancies are offered to women at increased risk for these problems generally because of advanced maternal age or an abnormal screening test. These tests are chorionic villus sampling which is performed at 10-12 weeks gestation and amniocentesis which can be performed early at 13-14 weeks or in the traditional time frame at 15 weeks or later. Both tests have a high degree of accuracy in detecting fetal chromosomal abnormalities and both are associated with an increased risk for miscarriage. Depending on the test, the risk for pregnancy loss is 1 percent or less.   The information provided by tests is beneficial for some families; others do not feel the information is helpful prior to delivery. Those families at increased risk for a baby with abnormalities will find it helpful to obtain further information from genetic counselors at Prenatal Wellness Center so that they can choose the testing, if any, that is appropriate for them. Editor's note: The preceding column was brought to you on behalf of Health 1st. Striving to bring various topics and representing numerous employee wellness organizations and committees on campus, this weekly column seeks to provide MUSC, MUHA, and UMA employees with current and helpful information concerning all aspects of health.     Friday, Sept. 1, 2006 Catalyst Online is published weekly, updated as needed and improved from time to time by the MUSC Office of Public Relations for the faculty, employees and students of the Medical University of South Carolina. Catalyst Online editor, Kim Draughn, can be reached at 792-4107 or by email, catalyst@musc.edu. Editorial copy can be submitted to Catalyst Online and to The Catalyst in print by fax, 792-6723, or by email to catalyst@musc.edu. To place an ad in The Catalyst hardcopy, call Island Publications at 849-1778, ext. 201.