Flashcards in PH: Congenital Malformations Deck (15):
What is teratogenesis?
It may be induced when at least two conditions are met: teratogens must get into contact with the developing foetus, and the contact must be during the phase where the organ systems are in the process of being formed.
When is teratogenesis most likely to affect development?
• 14 days gestation (conception to implantation): embryo well protected against maternal drugs, but not against radiation, for example.
• 14 days – 14 weeks (organogenesis): most vulnerable stage
• 14 weeks – delivery (foetal stage):
What are some of the most common teratogens?
• Rubella – exposure before 16 weeks deafness or congenital heart defects
• Radiation – if exposure is after implantation
• Using a sauna – increases CNS defects
• Cocaine – microcephaly, SID, prematurity
When is the most vulnerable period in pregnancy for the effects of teratogens?
14 days - 14 weeks (organogenesis phase)
At what stage in pregnancy is an embryo well protected against maternal drugs, but not radiation?
Up to 14 days gestation (conception to implantation)
How may maternal infection with rubella affect foetal development?
Exposure before 16 weeks deafness or congenital heart defects
How may radiation affect foetal development?
Can cause developmental problems
How may using a sauna affect foetal development?
Increases the risk of CNS defects
How may using cocaine during pregnancy affect foetal development?
Microcephaly, SID, prematurity
When may maternal rubella infection cause problems
Exposure before 16 weeks gestation --> deafness or congenital heart defects
What triggers can cause neural tube defects in a foetus?
Folate deficiency, taking valproic acid, Trisomy 18 syndromes, and point mutations (MTHFR)
What are the different types of genetic phenotype of Down's Syndrome
Robertsonian Translocation (part of 21 is on top of 14)
Why has their been a decline in neural tube defects recently?
> Improved screening (AFP and ultrasound)
> Supplementation (folate)
> Fortification (cornflakes, brussel sprouts)
> Improved diet
What congenital abnormalities are associated with Down's Syndrome?
Heart defects: AV septal defect, ventricular septal defect, patent ductus arteriosus.