Prenatal Screening & Testing

1. Prenatal Screening & Testing 5 March 2014 Rels300 / Nurs330

2. Prenatal Screening vs. Prenatal Diagnosis Screening: aim is to identify women who have increased risk factors (larger than the general population of pregnant women) for having a child with a congenital anomaly because women over 35 years of age at delivery have a statistically higher risk for fetal chromosome problems, maternal age is a risk factor that suggests screening Diagnostic tests: In contrast to screening tests, diagnostic testing identifies specific indicators of fetal abnormalities 300/330 - appleby

3. Prenatal Diagnosis and Medical Genetics Mount Sinai Hospital Joseph and Wolf Lebovic Health Complex Toronto, Ontario http://www.mountsinai.on.ca/care/pdmg 300/330 - appleby

4. Maternal Serum Screening (MSS) blood analysis is routinely offered to pregnant women between the 15th & 18th weeks of pregnancy measures the levels of certain substances present in a woman's blood during pregnancy abnormal levels can indicate the possibility of a neural tube defect (NTD) such as spina bifida, or anencephaly; or a chromosomal disorder such as Down syndrome MSS is not a diagnostic test 300/330 - appleby

5. 3 hormones involved Alpha-fetoprotein • produced by the fetus as it grows • small amounts cross the placenta into mother's bloodstream. • Below-average levels indicate an increased risk of Down syndrome • Above-average levels indicate an increased risk of spina bifida or anencephaly Human chorionic gonadotropin (hCG) • Above-average levels of this hormone indicate an increased risk for Down syndrome. Estriol • Below-average levels may indicate an increased risk for Down syndrome

6. Neural Tube Defects Spina bifida • opening in the bones around the spinal cord • often not covered by skin Anencephaly • brain and skull do not develop completely • brain may be absent, or only brain stem may be present • incompatible with continued life – babies may be stillborn, or die within hours or days One to two babies out of 1,000 are born with a neural tube defect • not linked to maternal age

7. MSS sensitivityHow accurate is it? Analysis of maternal serum, performed between 16 & 18 weeks detects • 85% of fetuses with open spina bifida • 95% of fetuses with anencephaly • 60% to 70% for Trisomy 18 and Trisomy 21 This means comparable rates of results are false positives, or false negatives. If pregnant women go on to have more invasive fetal testing (which is diagnostic and has a greater reliability), this introduces risks for the fetus

8. Ultrasound imaging is non-invasive and has no known accompanying fetal risks. Ultrasound • confirms the age of the fetus • confirms single or multiple pregnancy • determine the nuchal translucency measurement (thick skin fold at nape of neck which may indicate Down’s or congenital heart defects) • screening measure, not diagnostic – (40%-70% detection rate) • detailed ultrasound at 18 weeks can give information on fetal anatomy and growth; detect cardiac activity • structural abnormalities such as spina bifida can be detected • not all structural abnormalities can be detected by ultrasound 300/330 - appleby

9. March 2009 GUIDELINES FOR ULTRASOUND AS PART OF ROUTINE PRENATAL CARE (SOGC) Following discussion and results of previous studies, the SOGC recommends: Routine diagnostic prenatal ultrasound at 18 to 22 weeks gestation should be offered to each pregnant woman Women should be informed of the limitations of accurate diagnosis: detection rates vary from 25% to 71%, and partly depend on ultrasonographer and the equipment used; may suggest further investigation for anomalies No evidence that ultrasound poses any fetal risks If abnormalities detected, refer for counselling Currently, average of 2.1 ultrasound scans per delivery in Canada 300/330 - appleby

10. Amniocentesis is often offered to women 35 and older. genetic diagnostic test second trimester (15 – 16 weeks) fine needle is inserted through the abdomen and into the uterus 20 milliliters of amniotic fluid removed Amniocentesis Suspended in the fluid are fetal cells, which are grown in the lab. About two weeks after the sample is drawn, chromosomes from the cells are checked for abnormalities. 300/330 - appleby

11. Miscarriage With no amniocentesis, natural rate of miscarriage after 16 weeks is about 3%. With amniocentesis, the additional risk is about 0.5% (1/200), making the total risk about 3.5%. Leakage of amniotic fluid, spotting or cramping during the first 12 hours following amniocentesis Infection Infection following the procedure is extremely rare (1-2 in 3000); may develop fever, have chills, cramps or bleeding Injury to Fetus very small risk of the needle touching the fetus; no injuries reported Risks of Amniocentesis 300/330 - appleby

12. Chorionic Villus Sampling (CVS) performed for the same reasons as amniocentesis chorionic villus sampling is generally done during the first trimester (10-13 weeks), giving results much earlier than amniocentesis 2 forms: a thin tube, called a catheter, is inserted through the cervix and, under the guidance of ultrasound, is used to extract a small sample of the placenta or, a needle can be inserted through the abdomen to sample the placenta (rather than the amniotic fluid) With chorionic villus sampling, the sac enclosing the fetus is not disturbed. 300/330 - appleby

13. Risks of CVS Miscarriage natural pregnancy loss at 10 weeks is about 4% additional loss due to CVS is about 1%; total loss rate risk is about 5% Injury to Fetus 1992 WHO report - no significant incidence of limb abnormalities in women having CVS compared with the general population when the CVS is performed by experienced physicians at 10 weeks of pregnancy or later Spotting or cramping Some patients have some spotting or bleeding following the procedure. Infection Infection following the procedure is extremely rare 300/330 - appleby

14. Cordocentesis (percutaneous umbilical blood sampling) • Only done in high-risk pregnancies • 3% risk for miscarriage with procedure • Need for rapid chromosomal analysis • Umbilical cord contains fetal blood samples which are analyzed • Performed beyond 16 weeks • Highly accurate results

15. PRENATAL DIAGNOSIS and AGE • 2 to 3% of babies born have some type of major birth defect • risk of some problems, due to abnormal separation of genetic material (chromosomes), increases with the mother’s age. • about 50% of chromosomal anomalies involve Down Syndrome (Trisomy 21) • other 50% of chromosomal anomalies are caused by a variety of problems (e.g. deletions, translocations, damage) • any other chromosomal problems result in a severely affected baby or one which does not survive even to delivery (e.g. Trisomy 13, 18) • incidence of Down Syndrome and other chromosomal problems increases with age • at 35 years the risk of a chromosomal anomaly is about 1:200

16. Trisomy 21: Down syndrome(3 instead of 2 #21 chromosomes) People with Down syndrome have both physical and mental disabilities. • medical problems include congenital heart defects which may lead to early mortality • range of physical and mental abilities - there is no way to predict how serious any of the disabilities will be • gastrointestinal abnormalities such as obstructions of the esophagus or the duodenum are fairly common • may require surgery shortly after birth • higher than average incidence of acute lymphocytic leukemia

17. Pregnancy Termination Rates for Down Syndrome Fetuses 2009, UK Three babies are being aborted every day due to Down's syndrome, according to a study which shows the number of terminations has more than trebled in the last 20 years. http://www.telegraph.co.uk/health/healthnews/6440705/Three-babies-aborted-every-day-due-to-Downs-syndrome.html 1999 research program report: 53.2% of recorded Down syndrome fetuses were prenatally diagnosed and electively aborted Worldwide range of termination of DS fetuses in 1999: 26.7% in Alberta; 84% in Paris, France Over the 7 years of the study, prevalence of DS newborns decreased Increasing numbers of DS fetuses are aborted Current numbers suggest up to 90% of Down Syndrome fetuses are aborted 300/330 - appleby

18. The Problem With an Almost-Perfect Genetic World By AMY HARMONPublished: November 20, 2005 “Some bioethicists envision a dystopia where parents who choose to forgo genetic testing are shunned, or their children are denied insurance. Parents and people with disabilities fear they may simply be more lonely. And less money may be devoted to cures and education.” STRENGTH IN NUMBERS Genetic testing may adversely affect children with Down syndrome. 300/330 - appleby

19. Contrasting Views Lippman says that prenatal diagnosis is presented as: An aspect of “public health” designed to reduce the frequency of selected birth defects (p.167) She believes that women are pressured by society and physicians to undergo testing → COERCION Wertz & Fletcher say that women are reproductively empowered by prenatal tests, and that the tests support their ability to have healthy children (p.167) Do you think that prenatal diagnosis should be offered as an aspect of “public health”? Would you find prenatal testing empowering or coercive? 300/330 - appleby

20. Lippmansays that “society has malfunctioned because it cannot accommodate the disabled in its midst” • Does society have an obligation to adjust to disabled individuals? • Should society (or schools) accommodate people with disabilities? • Does having a child with a disability cause suffering, or is suffering caused by society’s discriminatory practices? 300/330 - appleby

21. Adrienne Asch: Prenatal Diagnosis and Selective Abortion “My moral opposition to prenatal testing and selective abortion flows from the conviction that life with disability is worthwhile and the belief that a just society must appreciate and nurture the lives of all people, whatever the endowments they receive in the natural lottery.” people with disabilities thrive in our society they take from others, but also contribute to families, friends, the economy they are full members of the human and moral community 300/330 - appleby

22. Sources: Prenatal diagnosis and selective abortion: A challenge to practice and policy. Adrienne Asch.  American Journal of Public Health. Washington: Nov 1999. Vol.89,  Iss. 11;  pg. 1649, 9 pgs http://proquest.umi.com/pqdweb?index=53&did=46115887&SrchMode=1&sid=1&Fmt=3&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1130866878&clientId=18854 300/330 - appleby

23. Will increased use of prenatal diagnosis shift social resources away from people with disabilities? Yes, I believe it will because: No, I don’t believe it will because: 300/330 - appleby

24. How accessible is genetic counselling? Nova Scotia, New Brunswick and Prince Edward Island Maritime Medical Genetics Service IWK Health Centre Halifax, NS 300/330 - appleby

25. Why do physicians recommend fetal assessment? Maybe because of this http://www.inclusiondaily.com/news/advocacy/wrongfulbirths.htm#013103 “We offer counseling about the latest prenatal screening testing options, which include: Screening OptionsFirst Trimester Maternal Serum TestingSecond Trimester Maternal Serum TestingFirst Trimester Ultrasound for women at increased riskSecond Trimester UltrasoundScreens that combine these tests Diagnostic Options Chorionic Villus Sampling (CVS) Amniocentesis Cordocentesis” http://www.iwk.nshealth.ca/index.cfm?objectid=58D5DD6E-B8B7-ECEB-376C092E8CA99974 http://www.iwk.nshealth.ca/index.cfm?objectid=11461952-0F64-187B-16F00751182E03D9 300/330 - appleby

26. Judge Orders Doctor To Pay Parents Over Daughter's BirthBy Dave Reynolds, Inclusion Daily Express; January 31, 2003 VANCOUVER, BRITISH COLUMBIA--A Supreme Court justice ruled this week that a physician must pay a divorced couple $325,000 for the "distress and expense" of giving birth to a child with Down syndrome. Justice Michael Catliff determined that Dr. Ken Kan was negligent when he did not order an amniocentesis test for Lui-Ling "Lydia" Zhang, of Vancouver, which likely would have found that her unborn daughter, Sherry, had Down syndrome. Zhang has said that she would have aborted her pregnancy had she known that before the baby was born in April 1997. Dr. Kan was ordered to pay $10,000 in damages to Zhang and $315,000 in damages and living costs to Simon Fung, the father with whom 5-year-old Sherry now lives in Los Angeles, California. Justice Catliff explained that the award would have been higher, but he cut the amount in half because the parents contributed to the situation themselves. The attorney representing Zhang and Fung said his clients will likely appeal the decision and argue for a larger award. During a 15-day trial in November, Zhang said that Fung could not accept that she had given birth to a child with a mental disability. Having Sherry "totally disrupted our plans," she explained. The couple's one-month-old marriage then began to fall apart, Zhang said. Zhang has seen Sherry just eight times in the last five years. 300/330 - appleby

27. GE3LS research stands for Genomics-related Ethical, Environmental, Economic, Legal and Social research • http://www.genomecanada.ca/en/ge3ls/ Dr. Steve Scherer of the Hospital for Sick Children and the University of Toronto “Dr. Scherer heads a team of the country’s leading geneticists, developmental pediatricians and genome scientists taking part in a 10-nation project studying autism. With funding from Genome Canada, the team is working on isolating genes that may make someone susceptible to autism. Once those genes have been identified, physicians will be able to diagnose the condition much earlier and treat it more effectively.” 300/330 - appleby

28. What will happen if (or when) there is a prenatal test to detect the likelihood (or certainty) that an expected child will be autistic? 300/330 - appleby