Definitions in Congenital Anomalies ✅ Flashcards
What % of live births are affected by congenital abnormalities?
3-6%
What % of neonatal deaths in the UK are caused by congenital abnormalities?
20-25%
What is congenital malformation defined as?
A defect in the structure of an organ or a part of an organ due to abnormal development
What proportion congenital malformations have a congenital cause?
1/4
What is the case with the cause of most congenital malformations?
They have multifactorial or unknown causes
What % of congenital defects are caused by teratogens?
5-10%
What is a teratogen?
Any chemical, maternal physical condition, or deficiency that can alter fetal development or function
Give 4 examples of teratogens
- Maternal alcohol or drug misuse
- Maternal anti-convulsant use
- Congenital infection
- Maternal disorders, e.g type 1 diabetes mellitus
What is disruption defined as?
An anomaly which occurs when a fetal structure starts growing normally, but growth is disrupted by something which disrupts the process
What can cause disruptions leading to rterminal limb defects as a result of disrupted blood supply?
- Amniotic bands
- Chorionic villus sampling
What causes amniotic bands?
Thought to be formed when amnion ruptures early and fetal limb is forced into chorionic cavity, resulting in vascular compression followed by necrosis
What do amniotic bands result in?
Absent digits or limbs
When can chorionic villus sampling result in a similar anomaly to amniotic bands?
If carried,, out too early in pregnancy (around 8-10 weeks)
How can chorionic villus sampling lead to disruptions leading to terminal limb defects?
Due to vascular disruption,potentially haemorrhage from injured chorionic villi
What is deformation defined as?
An external force that results in an alteration of shape of a previously normally formed structure
