Prenatal Screening and Diagnosis Flashcards
A 30-year-old G2P1 woman at 12 weeks gestation confides in you that she drinks 3 to 4 glasses of vodka most nights. Her medical and surgical history is otherwise unremarkable. You explain to her that the foetus is at increased risk for:
a) Cardiac defect
b) Cystic adenomatoid malformation
c) Macrosomia
d) Cleft lip and palate
e) Bowel obstruction
d) Cleft lip and palate
At her first prenatal visit at 9 weeks, an 18 year-old woman accepts the offer of HIV testing following counselling. The result comes back positive. She is asymptomatic and her CD4 cell count is 388/mm3. You counsel her that the benefit of initiating HAART therapy is:
a) Reduced risk of systemic moniliasis
b) Prevention of intrauterine growth restriction
c) Prevention of developing acquired immunodeficiency syndrome (AIDS) in pregnancy
d) Reduced of lymphadenopathy syndrome
e) Reduced risk of transmission of HIV to the fetus
e) Reduced risk of transmission of HIV to the fetus
An Ultrasound scan at 20 weeks can do all the following except:
a) Confirm gestation
b) Confirm there is only one fetus
c) Exclude fetal anomaly
d) Identify the placental site
e) Confirm that the fetal heart has 4 chambers
c) Exclude fetal anomaly
A 36-year-old primigravida woman at 15 weeks’ gestation has received genetic counselling and has chosen to proceed with prenatal diagnosis. She has read about chorionic villus sampling (CVS) and now consults you about the relative risks and benefits of CVS versus amniocentesis. In counselling this patient you emphasise:
a) The proven increased safety of CVS over amniocentesis
b) That CVS allows prompt diagnosis of neural tube defects
c) That she is beyond the appropriate gestational age for CVS
d) The improved accuracy of prenatal diagnosis from CVS
e) The risk of miscarriage associated with amniocentesis performed at 16 weeks gestation is 1/600
c) That she is beyond the appropriate gestational age for CVS
A healthy 26-year-old G1 P0 with no significant family history underwent nuchal translucency screening at 11 weeks gestation. The nuchal translucency measured 3.9mm. In a combined risk assessment with first trimester maternal serum screening the risk of trisomy 21 was given as 1 in47. She underwent chronic villus sampling and the karyotype was said to be normal (46 XX). The most appropriate next step is to:
a) Reassure that the fetus is most likely to be normal and this was a false positive screen
b) Reassure but offer amniocentesis as the result could be incorrect due to maternal cell contamination
c) Offer a detailed morphology scan including fetal cardiac scanning at 20 weeks gestation
d) Offer a detailed morphology scan at 16 weeks gestation
e) Offer termination of pregnancy because of the high likelihood that the fetus is abnormal
c) Offer a detailed morphology scan including fetal cardiac scanning at 20 weeks gestation
A 37 year old Primigravida, Mrs Swan, is referred to you at 15 weeks gestation by her lead maternity carer. Mrs Swan is very anxious about the possibility of her baby being affected by Down’s syndrome as her second cousin has a child who has this condition. She is happy to pay for any screening test that may be recommended. The most accurate screening test to offer is:
a) Serum Screening
b) Chorionic Villous Sampling
c) Non-invasive prenatal testing (NIPT)
d) Nuchal Translucency Scanning
e) Detailed 18 week anomaly scan
c) Non-invasive prenatal testing (NIPT)
A 35 year old woman has a brother with Down’s syndrome with a karyotype of 47 XY +21. She sees you at 12 weeks with a live intrauterine fetus. What is the risk of this fetus having Down’s syndrome?
a) 1 in 20
b) 1 in 100
c) 1 in 250
d) 1 in 500
e) 1 in 1000
c) 1 in 250
Routine blood tests on a 12/40 pregnant woman have come back with a positive VDRL (Venereal disease Research Laboratory titre of 1:4. You advise the woman:
a) She has syphilis and will require antibiotic treatment, but her baby will be normal
b) She has syphilis and her baby will have congenital syphilis syndrome
c) She has Yaws
d) A more specific RPR (Rapid Plasma Reagin) test is required prior to the diagnosis of syphilis
e) A more specific TPHA (Treponema Pallidum Haemagglutination Test) is required prior to the diagnosis of syphilis
e) A more specific TPHA (Treponema Pallidum Haemagglutination Test) is required prior to the diagnosis of syphilis
A 25 year old patient underwent an amniocentesis after a combined first trimester maternal serum screen and nuchal translucency scan gave a risk of 1 in 100 of the fetus having Trisomy 21. The amniocentesis was normal 46XY Karyotype. She asks you why the test was normal if the scan had showed high risk. You tell her it is due to:
a) The low prevalence of Trisomy 21 in the population
b) The possibility that the amniocentesis could be wrong but there is a low chance of this
c) The false positive rate of the test
d) The false negative rate of the test
e) The relatively low detection rate of the test leading to a high false positive rate
c) The false positive rate of the test
Which of the following can be a cause of polyhydramnios? :
a) Fraser syndrome
b) Duodenal atresia
c) Maternal pre-eclampsia
d) Duchenne Muscular dystrophy
e) Multicystic dysplastic kidney
b) Duodenal atresia
Ann is 34 years old and is 13 weeks into her first pregnancy. Her first trimester combined screening has returned as high risk, with a 1 in 180 risk of Trisomy 21. Which of the following is correct?
a) She does not require invasive testing as the risk of her baby having Trisomy 21 is <1%
b) She will require local anaesthetic and sedation if she has invasive testing
c) She cannot have an amniocentesis until 15 weeks gestation
d) The risk of miscarriage from amniocentesis is 1 in 90
e) Chorionic villus sampling is more accurate than amniocentesis
c) She cannot have an amniocentesis until 15 weeks gestation
Which is correct regarding fetal cardiac defects:
a) Cardiac defects occur in approximately 5% of live births
b) A fetus with Trisomy 21 is more likely to have a cardiac defect than a fetus with Trisomy 13
c) Pregnant women with uncontrolled diabetes have no increased risk from the general population of having a baby with a fetal cardiac defect
d) A chromosomal abnormality will be present in up to 30% of fetuses diagnosed with a cardiac defect
e) 95% of cases of fetal cardiac defects are diagnosed at the anatomy ultrasound at 18-20 weeks
d) A chromosomal abnormality will be present in up to 30% of fetuses diagnosed with a cardiac defect
Malia, a 32 year old statistician, is 9 weeks pregnant by LMP. She is interested in learning more about her options for screening for Down’s syndrome and other conditions. She is particularly interested in the detection and false positive rates for different screening modalities. You advise her that:
a) MSS1 screening for trisomy 21 has a 89% detection rate for a 5% false positive rate
b) MSS1 screening for trisomy 21 has a 80% detection rate for a 4% false positive rate
c) MSS2 screening has a 70% detection rate for a 5% false positive rate
d) MSS1 plus MSS2 screening has a 90% detection rate for a 5% false positive rate
e) NIPT (non-invasive prenatal testing) for trisomy 21 has a 97% detection rate for a false positive rate of 5%
b) MSS1 screening for trisomy 21 has a 80% detection rate for a 4% false positive rate
Madeleine, a 24 year old teacher, has come for her first antenatal visit. You discuss screening for Down’s syndrome and other conditions. She chooses the option of MSS1 screening. You advise her that the BEST time for her MSS1 blood tests and nuchal scan to screen for trisomy 21 is:
a) Blood test at 9 weeks and nuchal scan at 10 weeks
b) Blood test at 10 weeks and nuchal scan at 12 weeks
c) Blood test at 11 weeks and nuchal scan at 11 weeks
d) Blood test at 12 weeks and nuchal scan at 13 weeks
e) Blood test at 13 weeks and nuchal scan at 10 weeks
b) Blood test at 10 weeks and nuchal scan at 12 weeks
