Ch 17 Prematurity Flashcards
 Prematurity is defined as
Birth that occurs before 37 weeks
Immaturity of body systems
What is often used as a proxy for gestational age?
Birthweight
Birth weight classifications
Low birth weight 5lb 8oz
Very low birth weight 3lbs 5oz
Extremely low birth weight 2lbs 3oz
Micropremature 1lb 10oz
Gestational age classifications
Late preterm birth <37
Very preterm <33
Extremely preterm <29
Micropremature <26
Pre term infants are at risk for what kinds of neurological complications?
Periventricular hemorrhagic infarction (PVHI) Periventricular leukomalacia (PVL)
Describe sequence of PVHI
sequence of events begin with reductions in cerebral oxygen and blood flow (hypoxia ischemia)
result in intraventricular hemorrhage, and then PVHI
Other neurological complications in premature infants?
Post hemorrhagic hydrocephalus
Focalized neuronal injury
Cerebral ischemic lesions
Another kind of neurological complications in preterm infants?
Hypoxic ischemic encephalopathy with corresponding presentation such as:
poor Apgar scores
cord blood metabolic acidosis
need for resuscitation
How many grades of intraventricular hemorrhage are there
4
Grade I of IVH
Bleeding into germinal matrix
Grade II of IVH
Bleeding into ventricles, but no ventricular dilation
Grade III of IVH
Bleeding resulting in ventricular dilation
Grade IV of IVH
Large hemorrhage with PVHI in parenchyma
Risk factors for premature birth
Maternal hx of previous preterm birth
Short spacing between pregnancies multiple birth pregnancy
Maternal age younger than 16 older than 35
Maternal health problems (diabetes, obesity, HBP, kidney disease, heart disease, infections, stress)
Uterus or cervix abnormality
Alcohol, drugs, cigarette use
Low SES
Lack of prenatal care
Black
% of preterm births in US
10%
- 7% late preterm <37 weeks
- 3% <33 weeks
% of low birth weight in the US
8% low BW
1% very low BW
What factor accounts for the majority of preterm and low birth weight?
Multiple births
Infant mortality rate in the United States
6 per 1000 births