Incidences Flashcards
What is the incidence of dizygotic twins?
1/80 pregnancies and accounts for 90% of twinning
What is the incidence of monozygotic?
3/1000 pregnancies
What is the incidence of triplets?
Non: 1/1000
identical: 1/10,000
What is the incidence of conjoined twinning
1/250,000 live births
What is the incidence and pattern of inheritence in Robin sequence in robin sequence?
1/8500
Autosomal dominant
What % of treacher-collins is caused by new mutations?
60%
What is the incidence of cleft lip ± palate?
1/700-1000
what % of newborns are born w/ a major and minor anomaly?
3% - major
15% - minor
What are the %’s of the 3 causes of T21?
95%: non-dysjunction (M1 most between homologous chromosomes and M2 less common between sister chromatids)
4% unbalanced translocation
1% mosaicism
How many pregnancies are ectopic?
2%
What do 20% of people w/ situs inversus have?
Kartanger’s syndrome
What is the percentage of false +ves in combined test?
What is its detection rate?
5%
80%
What are the risks of miscarriage CVS and amniocentesis?
CVS: 1-2%
Amnio: 0.5-1%
how many spina bifida pts have hydrocephalus?
15%
What are the percentages of the different types of membranes in MONOZYGOTIC twins?
Dichorionic diamnotic: 25-30%
Monochorionic diamniotic: 70-75%
Monochorionic monoamniotic: 1-2%
What are the percentages of the different types of membranes in DIZYGOTIC twins?
Dichorionic diamnotic: 58%
Monochorionic diamniotic: 42%
What % does TTTS + TRAP occur in monochorionic twinning?
TTTS (10-15%)
TRAP (1%)
What is the incidence of Edward’s syndrome?
1/5000 live births
What is the incidence of patau’s (T13)?
1/20,000 live births
What is the incidence of prader-willi syndrome?
1/15,000
what is the incidence of kleinfelter’s syndrome?
1/500
What % of couples are infertile?
15% (90% subfertile)
What is the incidence of endometriosis?
1/10
what is the incidence of ASDs? Do they occur equally in males and females?
- 4/10,000 births
2: 1 F:M
What is the incidence of VSD?
12/10,000 (commonest CHD)
What is the incidence of TOF?
9.6/10,000 births
What is the detection rate of anencephaly + myelomeningocele on the fetal anomaly scan?
90%
what % of NTDs are prevented by folic acid supplimentation?
50-70%
What is the incidence of limb defects? Are upper or lower limbs more affected?
6/10,000 live births
upper>lower
What is the incidence of oesophageal atresia?
1/2500-4000 births
What is the incidence of omphalocele?
2.5/10,000 births
What is the prognosis of omphalocele?
25% mortality rate
What is the incidence of gastroschisis?
2-3/10,000 births
What is the incidence of pre-eclampsia?
5% (1/20 pregnancies)
What is the incidence of placenta previa?
0.5% (1/200 pregnancies)
what is the incidence of hypospidiasis?
3-5/1000 births
what is the incidence of epispidiasis?
1/30,000 births
What is the incidence of cleft palate only?
1/1500-2500
What is the incidence of placental abruption?
1/200
what is the incidence of CLP?
1/700-1000
What is the incidence of exencephaly?
1/5000
What is incidence of horseshoe kidney?
1/600
