antenal screening Flashcards
what is detection rate?
the proportion of affected individuals who will be detected by screen test
what is false positive rate?
the proportion of unaffected individuals with a positive screening result.
what is false negative rate?
the portortion of affected individuals with negative screening rate
what are the fetal screening programme offered?
Down’s (trisomy 21)
Edward’s (18)
Patau’s (13)
what are the infectious disease screening programme?
Hep B
HIV
Syphilis
What is the new born blood spot screening test for?
cystic fibrosis
congenital hypothyroidism
sockle cell disease
inherited metabolic disease
Facts on Down’s?
Affects about 1 in every 1000 births
Incidence increases with maternal age
40-45% have a heart defect
Increased incidence of childhood leukaemia, epilepsy, thyroid disorders and many will develop Alzheimer’s in later life
Facts on Edward’s
T18 affects about 3 of every 10,000 births
Incidence increases with maternal age
Most babies with Edward’s will die before they are born, be stillborn or die shortly after birth
All babies born with T18 will have a wide range of problems, which are usually extremely serious.
Babies affected by T18 can have heart problems, unusual head and facial features, major brain abnormalities and growth problems
Facts on Patau’s syndrome
Incidence increases with maternal age
T13 affects about 2 of every 10 000 live births (3rd most common Trisomy)
Most babies with Patau’s will die before they are born, be stillborn or die shortly after birth
Associated with multiple severe fetal abnormalities
80% have congenital heart defects
Holoprosencephaly
Midline facial defects
Abdominal wall defects
Urogenital malformations
Abnormalities of hands and feet
what is holoprosencephaly?
the brain doesn’t divide into two halves
Screening for T21,18,13?(1st trimester)
Combined test (1st tremester): nuchel (nape of the neck) transluency test and serum test
Screening for T21,18,13?(2nd trimester)
Quadruple test- serum test only
Alpha Feto Protein
total Beta HCG
Oestriol
Inhibin A
Ultrasounds cans in pregnancy?
2 during pregnancy offered
- Early Ultrasound Scan usually between 10 to 14 weeks gestation used mainly for dating the pregnancy and confirming viability
- Ultrasound to screen for structural anomalies ideally between 18 weeks 0 days and 20 weeks 6 days gestation
Exomphalos vs gastroschisis
Exomphalos (omphalocoele) is a central abdominal wall defect that allows herniation of abdominal viscera into the umbilical cord
Gastroschisis is a smaller defect in the abdominal wall, located to the right side of the anatomically normal umbilical cord
what are the two types of thalassaemias?
Alpha Thalassaemia major is incompatible with extrauterine life.
Beta Thalassaemia major results in life threatening anaemia and requires blood transfusions every 4 – 6 weeks and iron chelation therapy 5 – 7 times weekly.
