| There are two types of prenatal Down syndrome | | | | this chromosomal disorder. However, these |
| screening tests. Screening tests can let you know if | | | | procedures are more invasive and sometimes result |
| your baby does not have this chromosomal disorder, | | | | in a miscarriage or other complications. Typically, |
| while later diagnostic tests can confirm that the fetus | | | | doctors only perform these tests on women over |
| does, in fact, have Down syndrome. Generally | | | | 35, if genealogy warrants it or if they've tested |
| screenings are done around 11 weeks and later tests, | | | | positive in the initial screening. Amniocentesis, |
| between the 15th and 20th week of gestation, are | | | | performed from 16 to 20 weeks, uses a needle to |
| performed if there is reason to believe the baby may | | | | remove a small amount of amniotic fluid from the |
| be at risk. | | | | womb. |
| Screening tests are very non-invasive and relatively | | | | While it's an out-patient treatment, women may |
| painless. These Down syndrome screening | | | | experience cramping, bleeding and infection, not to |
| procedures are primarily done to let parents know | | | | mention that 2-3% of patients lose their baby. As a |
| whether or not they want further testing done. One | | | | result, amniocentesis is not recommended before the |
| screening test for Down syndrome is called Nuchal | | | | 14th week of gestation. Chorionic villus sampling and |
| translucency testing, which is performed between 11 | | | | percutaneous umbilical blood sampling are other |
| and 14 weeks of pregnancy. | | | | alternatives. |
| Using ultrasound, doctors can measure the space in | | | | With chorionic villus sampling, a small sample of |
| the folds of tissue behind a baby's neck where | | | | placenta is removed through a needle inserted into |
| excess fluid typically accumulates for babies with | | | | the abdomen. This Down syndrome screening can be |
| Down syndrome. This procedure accurately predicts | | | | done between the 10-12th weeks of gestation. Rate |
| Down syndrome 80% of the time. Additionally, a | | | | of miscarriage following the procedure is 3-5% and |
| blood test called "the triple screen" or "multiple | | | | the use of CVS before the 10th week of pregnancy |
| marker test" is also performed at the 15-20 week | | | | resulted in babies with missing or shortened fingers or |
| mark. Doctors will check the blood for alpha | | | | toes. At the 20-week mark, percutaneous umbilical |
| fetoprotein plus, plasma protein-A and the hormone | | | | blood sampling (PUBS) can test for Down syndrome. |
| chorionic gondatropin. | | | | A small sample of blood is removed from the umbilical |
| The second type of Down syndrome diagnostic | | | | cord and the risks are comparable to amniocentesis. |
| tests are about 99% accurate in detecting signs of | | | | |