prenatal diagnosis

Question 1

objective of prenatal diagnosis

Answer 1

detect lethal/life threatening abnormality/causing severe mental health handicap

planned care

option of TOP

Question 2

methods for prenatal diagnosis

Answer 2

history

maternal serum screening

US

invasive procedures

Question 3

important points of history for prenatal diagnosis

Answer 3

maternal age - increases chromosomal abnormalities risks

downs syndrome more common in younger mums

maternal diseases - diabetes - 10/12 week period - increase risk of congenital cardiac malformations and neural tube defects

epilepsy - anti epileptics increase risk esp neural tube defects

previous obstetric history
- previous child w aneuploidy

genetic disorder - autosomal recessive and dominant

structural abnormality

cosanguinity

parent with known balanced translocation

exposure in pregnancy-drug related malformations-antiepileptcis, warfarin, Vit A

intrauterine infections - rubella (rash in pregnancy), CMV, parovirus, zika virus (travel)

Question 4

what maternal blood screening is done

Answer 4

haemoglobinopathy

• thalassaemia
• sickle cell disease

VDRL screening - syphillis

AFP screening

Down’s serum screening

Question 5

what is AFP

Answer 5

AFP is produced in fetal liver and small bowel

Question 6

what is AFP screening

Answer 6

raised level ass. with open neural tube defect, gastroschisis, cystic hygroma, congential nephrosis, teratoma, fetal infection, oesophageal atresia

wrong dates, multiple pregnancy, bleeding

late pregnancy problems

Question 7

1st trimester combined screening tests for

Answer 7

trisomy 21 downs
18 edwards
13 patau

Question 8

when is downs syndrome screening done

Answer 8

1st and 2nd trimester

15-18 weeks

Question 9

what hormones do we look for in downs syndrome and what are the levels

Answer 9

AFP

BHCG

in downs lower AFP and higher BHCG

Question 10

1st trimester screening what do we do

Answer 10

nuchal translucency measurement

• fetal neck in neutral position, sagittal section
• at least 3 measurements

Down’s syndrome, cystic
hygroma, cardiac malformations, thoracic
compressive syndromes-congenital
diaphragmatic hernia, congenital infections

Question 11

what can be done in 1st trimester USS

Answer 11

Viability
• Accurate dating
• twin determination and chorionicity
• detection of fetal abnormalities anencephaly, large anterior abdominal wall
defects, cystic hygroma
• measurement of nuchal translucency

Question 12

what can be seen in detailed USS

Answer 12

18-20 weeks
routine anomaly scan
• Measurements (growth)
• viability
• liquor volume
• fetal anatomy
• placental location
• assessment of soft markers for aneuploidyrenal pelvic dilatation, choroid plexus cysts