Doesn’t determine risk for NTD. o Amniocentesis （（（（（ Netural tube defects (NTD): spina bifida （（（ , anencephaly （（（（（（ . Chromosomal disorders: e.g. trisomy 21 (Down syndrome), 18. Genetic disorders: cystic fibrosis （（（（（（ , Turner syndrome. 3 rd trimester to test lung maturity . Specific tests depend on personal/ family medical history. Miscarriage risk: 0.3% o Chorionic Villus （（ Sampling (CVS) Earlier diagnosis and rapid results. Performed 10-12 weeks of gestation. Removal of small tissue specimen from fetal portion of placenta , chorionic villi originate in zygote （（（ , tissue reflects genetic makeup of fetus . Miscarriage risk: 1%. o Fetal Blood Sampling (PUBS) Direct access to fetal circulation, insertion of needle directly into a fetal umbilical vessel under ultrasound guidance. Know: o Screening vs. diagnostic Screening reveals the possibility of a problem or abnormality, usually stated as risk of or chance of . Maternal health problem, fetal characteristics: sex, size, gestational age, presentation, placenta, amniotic fluid, paternity （（ , infection. Sequential screen: for most women, it is a two-step process , step one is done between 11-13 weeks, step two is down between 15-20 weeks. Step one combines a nuchal translucency ultrasound with a blood test . This blood test measures a pregnancy-related protein called PAPP-A . There are no results reported from step one unless the risk for Down syndrome is at least 1 in 40 . Women who receive a result after step one will not go on to step two. Women who do not receive a result from step one will go on to step two . Step two is a second blood test . This blood test measures four pregnancy-related proteins: AFP, estriol, hcg, and inhibin A. advantage: this test provides an early result for pregnancies with the highest risk for Down Syndrome . Two-step screening tests, like sequential screening, hav a lower screen positive rate than one-step screening tests. Disadvantage: most women will not go results until after 15 weeks. Integrated serum screen: serum integrated screening is a two-step process . Step one is done 11-13 weeks. Step two is done 15-20weeks. Step one is a blood test , this blood test measures a pregnancy-related protein called PAPP-A , there are no results reported from step one . Step two is a second blood test , this blood test measures four pregnancy-related proteins: AFP, estriol,hcg, and inhibin A . results are reported after this step. Advantage: this is the best test for women who do not have access to a nuchal translucency ultrasound. Two-step screening tests, like serum integrated screening, have a lower screen positive rate than one-step screening tests . Disadvantage: this test has a lower detection rate for Down syndrome than other two-step screening tests. There are no results until after 15 weeks.
FALL 2015 NURS450 STUDY GUIDE EXAM 2 Diagnostic: determine with a relative certainty whether a fetus has a specific problem or abnormality .
- Spring '14
- Obstetrics, Down syndrome, Study Guide Exam, Late pregnancy