Birth Defects Flashcards
What does disturbances in carbohydrate metabolism during pregnancy in diabetic mothers cause?
A high incidence of stillbirths, neonatal deaths, abnormally large infants, and congenital malformations.
What is the risk of congenital anomalies in the offspring of diabetics with long-standing disease?
The risk of congenital anomalies has been reported to be as high as 80%.
Is insulin a teratogen?
NO!
What are the factors responsible for abnormalities?
They have not been identified, evidence suggests that altered glucose levels play a role.
True OR False:
A significant correlation exists between the severity and duration of the mother’s disease and the incidence of malformations.
True
What reduces the occurrence of malformations?
Strict control of maternal metabolism with aggressive insulin therapy prior to conception.
What is the risk of congenital anomalies in children born to mothers with pregestational diabetes (both Type 1 [insulin dependent] and type 2 [non-insulin dependent] )?
three to four times higher
Increased risk for a wide variety of malformations such as?
neural tube defects congenital heart defects caudal dysgenesis (sirenomelia)
What is caudal dysgenesis (sirenomelia) usually fatal due to?
It is usually fatal due to anomalies in the kidneys and bladder.
What is Phenylketonuria (PKU)?
An autosomal recessive metabolic genetic disorder characterized by a mutation in the gene for the hepatic enzyme phenylalanine hydroxylase (PAH).
What is PAH necessary for?
PAH is necessary to metabolize the amino acid phenylalanine (Phe) to the amino acid tyrosine.
What are mothers with PKU at risk for having infants with?
intellectual disability
microcephaly
cardiac defects
How do mothers with PKU reduce the risk?
Keep a low-phenylalanine diet before conception and during pregnancy.
What can untreated PKU lead to?
Mental retardation, seizures, and other serious medical problems.
When is the diagnosis for PKU usually made?
At birth, PKU is commonly included in the newborn screening panel of most countries.
Patients diagnosed early who keep a strict diet will have?
A normal life span with normal mental development.
Are nutritional deficiencies teratogenic?
YES! Especially vitamin deficiencies.
What does poor maternal nutrition prior to and during pregnancy contributes to?
low birth weight and birth defects
What causes endemic cretinism and what are it’s characteristics?
Iodine deficiency and it is characterized by stunted mental and physical growth.
Another name for Congenital Hypothyroidism?
Cretinism
How does Cretinism occur?
Can be endemic, genetic, or sporadic.
What does sporadic or genetic cretinism result from?
Abnormal development or function of the fetal thyroid gland.
Is genetic or sporadic cretinism common in developed countries?
NO! Almost completely eliminated in developed countries by early diagnosis by newborn screening schemes followed by lifelong treatment with thyroxine (T4).
What happens if cretinism is left untreated?
If untreated, results in mild to severe impairment of both physical and mental growth and development.
In 2007 to 2008, how many women of reproductive age were obese (Body Mass Index >30)?
over 1/3
What is pregnancy obesity associated with risks for?
neural tube defect (risk is 2 times more)
heart defects, omphalocele, and multiple congenital anomalies.
Why does pregnancy obesity cause congenital anomalies?
May relate to metabolic disturbances.
Hypoxia induces congenital malformations in animal models.
Children born at a high altitude are lighter in weight and smaller than those born near or at sea level, no increase in the incidence of congenital malformations has been noted.
In Japan the contamination of fish with high levels of organic mercury resulted in?
Children with multiple neurological symptoms similar to cerebral palsy (seizures, irritability, jitteriness, feeding and respiratory problems, and lethargy).
Lead increases rate
Abortions, growth retardation, and neurological disorders..
The assessment of growth and development of the fetus in utero, is usually performed by?
Ultrasound, amniocentesis, chorionic villus sampling (CVS), and maternal serum screening.
In combination, these techniques are designed to detect?
Malformations, genetic abnormalities, fetal growth, and complications of pregnancy, such as placental or uterine abnormalities.
Ultrasonography
Noninvasive technique that uses high- frequency sound waves reflected from tissues to create images.
2 approaches of ultrasonography
transabdominal or transvaginal
Extra: transvagnial produces images with higher resolution
Important parameters revealed by ultrasound include:
characteristics of fetal age and growth;
presence or absence of congenital anomalies;
status of the uterine environment, including the amount of
amniotic fluid;
placental position and umbilical blood flow;
and whether multiple gestations are present
Amniocentesis
The transabdominal sampling of amniotic fluid and fetal cells. Performed at weeks 14-18.
Amniocentesis is indicated when?
woman is over 35 years
Previous child with a chromosomal anomaly •
One parent is a known carrier of a translocation or
inversion
One or both parents are known carriers of an X-linked
recessive or autosomal recessive trait
There is a history of neural tube defects
The sample of amniotic fluid obtained is used in what studies?
- a-Fetoprotein assay
- Spectrophotometric assay of bilirubin
- Lecithin-sphingomyelin (L/S) ratio and phosphatidylglycerol assay
- DNA analysis
What is a-Fetoprotein assay used to diagnose?
neural tube defects
What is Spectrophotometric assay of bilirubin used to diagnose?
hemolytic disease of the newborn
What is Lecithin-sphingomyelin (L/S) ratio and phosphatidylglycerol assay used for?
To determine lung maturity of the fetus.
What is DNA Analysis used to diagnose?
Chromosomal abnormalities and single-gene defects.
Chorionic Villus Sampling is used for?
Sampling of the chorionic villi to obtain a large amount of fetal cells for DNA analysis.
2 approaches of chorionic villus sampling
transabdominal or transcervical
When is Chorionic villus biopsy is performed?
weeks 6-11 (earlier than amniocentesis)
