Tools of Prenatal Diagnosis

1. Tools of Prenatal Diagnosis Julie Moldenhauer, MD Reproductive Genetics Maternal Fetal Medicine Obstetrics and Gynecology

2. Objectives: • Discuss various prenatal screening and testing tools • Discuss the timing of the various tools in gestation • Discuss benefits and risks of various options • Review the difference between screening and testing

4. Baseline Risk for Birth Defects in the General Population is 3-5%

5. Structural Abnormalities • Congenital heart disease • Spina bifida • Gastroschisis • Chromosomal Abnormalities • Trisomy 21 • Triploidy • Infections • Parvovirus • Cytomegalovirus • Toxoplasmosis • Growth Abnormalities • Hematologic Abnormalities • Anemia • Thrombocytopenia • Functional Defects • Arthrogryposis • Renal dysfunction • Syndromes • Skeletal Dysplasia • Diabetic embryopathy What Can We Diagnose in the Prenatal Setting?

6. Prenatal Diagnosis Tools • History**** • Personal History • Family History • Population Screening • Serum Screening • Ultrasound • Fetal MRI • Invasive Diagnosis • Chorionic villus sampling • Amniocentesis Oaklandcc.edu

7. History is a Screening Tool! • Medication Exposures • What medications? • When was the exposure? • Environmental Exposures • Does she work in a preschool and was exposed to parvovirus? • Is she exposed to high doses of radiation? • Family History • Brother with hemophilia • Uncle with cystic fibrosis • Ethnic background • Consanguinity • Maternal Age • > 35 years at delivery • Obstetric History • Prior baby born with Down syndrome • Prior stillbirth • Medical History • Is mom diabetic? How well controlled is her sugar? • Does she have PKU? • Is she hypertensive?

8. As maternal age increases, the risk for aneuploidy increases. This is due to maternal meiotic nondisjunction. Maternal age > 35 at the time of delivery is considered “Advanced Maternal Age” or AMA

9. Down syndrome phenotype caused by trisomy 21 Down syndrome phenotype caused by 14;21 translocation • The risk for recurrence of chromosome abnormalities is dependent upon the genetic mechanism involved. • Trisomy: 1% or maternal age-related risk • Translocation: • Maternal carrier: 10-15% • Paternal carrier: 2%

10. Maternal Diabetes: Reproductive Risks • Obstetric • Spontaneous preterm labor • Polyhydramnios • Preeclampsia (15-20%) • Intrauterine growth restriction • Shoulder dystocia • Cesarean delivery • Fetal and Neonatal • Congenital anomalies: 6-12% • Intrauterine fetal demise • Macrosomia – Shoulder dystocia • Growth restriction • Hyperbilirubinemia • Hypoglycemia • RDS • Polycythemia • Organomegaly • Long term – obesity and carbohydrate intolerance Caudal Regression Syndrome ACOG Practice Bulletin #60: Pregestational Diabetes Mellitus, March 2005

11. Teratogen Exposure

12. Teratogen Exposure • Examples: • Accutane • ACE inhibitors • Lithium • Antiepileptic drugs (AEDs) • Anticoagulants: warfarin • Antidepressants • Methotrexate • Thalidomide • Fetal effects are timing and dose dependent • Each medication is assigned a pregnancy category based on available data; A-D, X • www.Reprotox.org • www.otispregnancy.org

13. Ultrasound images of fetal hydrops – abnormal collection of fluid in multiple body compartments. Mom works at a daycare where there was a Parvovirus B19 or Fifth Disease outbreak 4 weeks ago. Parvovirus causes fetal aplastic anemia that can be life-threatening.Suspicion of diagnosis by altered maternal serum titers of Parvo IgG and IgM and confirmed by amniotic fluid PCR for Parvo. Confirmed Parvo infection in a fetus with hydrops can be treated with intrauterine blood transfusions.

14. = MR = asthma = TSC 6 2 2 n n

15. Fetal Ultrasound Showing Cardiac Rhabdomyoma Fetal MRI Showing Tubers Prenatal Findings Consistent with Tuberous Sclerosis Confirmed as Neonate

16. Screening for Genetic Disease Ethnic Group Disease African American Sickle Cell Disease: 1/12 Mediterranean Beta-Thalassemia: 1/30 Southeast Asian Alpha-Thalassemia: 1/20 Caucasian Cystic Fibrosis: 1/25

17. ASHKENAZI JEWISH ANCESTRY GENETIC CARRIER TESTING ACOG Committee Opinion Number 298, August 2004

18. Testing and screening options should be made available to all pregnant women

19. Prenatal Screening & Testing *First and Second Trimester Integrated and Sequential Screening

20. Test Performance • Detection rate – the percentage of affected that are test “positive” • (the higher, the better) • False positive rate – the percentage of unaffected that are test “positive” • (the lower, the better)

21. Goals in Prenatal Screening: • High sensitivity - low false positive rate • Wide availability • Reproducibility and accuracy • Human error, testing conditions

22. First Trimester Screening • 11-13 6/7 weeks (CRL 39-79 mm) • Maternal serum sample for PAPP-A and Free b-HCG • Ultrasound for Nuchal translucency • Detection Rates: • 80% for Trisomy 21 • 90% for Trisomy 18 • Does not screen for NTDs

23. Increased NT vs Cystic Hygroma • Increased NT > 95th% • With or without septations • Structural defects • Heart defects most common • Syndromic associations • Chromosomal defects • Exponential increase with increased NT • 50% Down syndrome • 25% Trisomy 13 or 18 • 10% Turner Syndrome • 5% Triploidy • 10% other NT > 3 mm is ABNORMAL

24. Second Trimester Serum Screening: Chromosome Abnormalities • Maternal Serum Screening • 15-20 weeks • Triple screen: 60% for T21 • Quad screen: 70% for T21 • Gestational Age Dependent** • Targeted Ultrasound • 50% aneuploid fetuses will have ultrasound markers

25. Prediction SURUSS 100 81% 74% 80 FASTER 66% 76% 69% 60 59% 42% DR at 5% FPR 40 37% 30% 20 0 AGE +AFP +hCG +uE3 +InhA single double triple quadruple 2nd trimester Serum Screening Test Performanceat a fixed 5% False Positive Rate(Dating by Ultrasound) Wald et al. 2000 Malone et al. 2005

26. Second Trimester Serum Screening: Neural Tube Defects • Neural Tube Defects • Spina Bifida • Anencephaly • AFP increased in “open” defects • Sensitivity • 90% anencephaly • 80-85% open spina bifida • False positive – 3-4%

27. Interpreting a Quadruple Screen Bottom Line: AFP is increased with NTDs and decreased with chromosome abnormalities

28. Elevated MSAFP • Incorrect Dates – most common reason • Multiples • Congenital Nephrosis • Ventral Wall Defects • IUFD • Adverse Pregnancy Outcomes • Stillbirth • Placental abruption • Preterm labor • Oligohydramnios • IUGR

29. Ultrasound detection of aneuploidy

30. Second trimester sonographic markers of Down syndrome Nuchal Fold Duodenal atresia Pyelectasis CPC Clinodactyly AV Canal

31. Trisomy 18Edward Syndrome • Close to 90% detected by prenatal scan • US: • Growth restriction • Clenched fists • >90% with cardiac defects • Multiple malformations • Grim prognosis • 50% Stillbirth • 50% die within the first week • 5-10% survive the first year

32. Trisomy 13Patau Syndrome • > 90% detected prenatally • US findings: • Midline defects including clefts, holoprosencephaly and NTDs • >90% have cardiac defects • Multiple structural abnormalities • Grim prognosis • High rate of miscarriage • 80-85% die within first month • 80-85% die within first year

33. Fetal Anatomy by Ultrasound • Routinely offered with prenatal care • Performed in the second trimester • 18-20 weeks optimal • Basic guidelines • Level of performance dependent upon • Who performs the scan • Where the scan is performed • Level of equipment

34. Gastroschisis Ventral Wall Defect Located to the Right of the Umbilicus with NO Membrane Covering Elevated MSAFP Levels Not Associated with Chromosome Abnormalities Increasing Incidence 1/10,000 >>>2-3/10,000

35. NTDs • Ultrasound detects 90-95% • Detection up to 98% with Ache by amniocentesis • 100% detection for anencephaly • Role of Folic Acid in Prevention: • All patients 0.4 mg per day • Previously affected 4mg per day • One month prior to conception and throughout first trimester • Decrease recurrence by up to 70%

36. Banana Sign Lemon Sign Meningomyelocele Sac Meningomyelocele Sac on Newborn

37. PGD: Preimplantation Genetic Diagnosis

38. Pearls for Invasive Testing Risk for Sensitization Mom Rh negative – Rhogam Other antibodies may increase risk Risk for Infection transmission Hepatitis B Hepatitis C HIV Need to know familial mutations prior to performing invasive testing

39. Chorionic Villus Sampling • Performed 10-14 weeks • Does not test for ONTD • Technique – “Placental biopsy” • Transabdominal • Transcervical • Risk for limb reduction defects if performed < 9 weeks • Loss rate 1/100-1/200 • Risk for mosaicism (~1%)

40. CVS Transcervical Transabdominal Performed at 10-14 weeks

41. Amniocentesis > 15 weeks Loss rate 1/200 (probably closer to 1/300-1/500) Tests for ONTD Technique Fine gauge needle Ultrasound guidance Aspiration of 20-30 cc of fluid

42. AMNIOCENTESIS PERFORMED ROUTINELY 15-20 WEEKS Ultrasound Guided Procedure

43. Cordocentesis • Percutaneous Umbilical Blood Sampling • Loss rate 1/100-1/200 • Typically done after 18 weeks • Ability for: • Rapid karyotype • Blood/platelet counts • Direct fetal injections/transfusions

44. Fetal Blood Sampling “PUBS”

45. Conclusions • Many options for screening and testing. • Prenatal screening should provide the most effective test to the greatest number of women. • The best method of screening is yet to be determined. • Patient preference should be considered. • Testing and screening should be available to all women.