Module 14 : Amniotic Fluid Flashcards
what are 6 things that amniotic fluid provides
- protection from physical trauma
- allows for growth
- provides a stable temperature for the fetus
- enables normal development of bones and muscle
- aids in maturation of lungs and GI tract
- may provide some nutrients
what produces amniotic fluid in the first trimester
- chorion frondosum
- membranes
- skin
- GU tract and lungs
MOSTLY FROM CHORIOAMNIONIC MEMBRANES
what produces amniotic fluid in the first trimester
- produced primarily by kidneys
- small amount by lungs
how is the fluid removed
- fetus drinks it
how does the fluid move through the fetus
- fetus swallows it
- fluid goes through fetal GI tract and absorbed by the small bowel
- kidneys excrete urine back into the amniotic cavity
what abnormality in fetus will cause polyhydramnious
- any high GI obstruction
- swallowing deficits
what abnormality in fetus will cause oligohydramnious
- bilateral GU obstruction
- renal agenisis
is evaluating amniotic fluid subjective ?
- yes
what are the 2 measurements of amniotic fluid
- maximum vertical pocket
- AFI
how is the maximum vertical pocket measured and what measurement indicated poly
- deepest pocket that is free of umbilical cord or fetal parts
- 8 cm
how is the AFI done
- largest pocket in each quadrant is measured anterior to posterior then added together
what the normal range for AFI
5-25cm
< 5 = oligo
> 25 = poly
when is the maximum level of amniotic fluid and when does it start to diminish
- may reached at 22 weeks and maintain until 32 weeks
- at 34 weeks begins to diminish
what is the minimum amount of fluid required fro fetal breathing
1cm
how would one determine if there was poly subjectively
- fetus floats freely in amniotic fluid
(should be touching uterus on at least 2 sides of uterus) - > 8cm pocket
- > 25cm AFI
what are 7 causes of poly
- diabetes mellitus
- CNS
- high GI obstruction
- hydrops
- TTTS
- musculoskeletal dysplasias
- idiopathic
what is the most common cause of poly
- diabetes mellitus
- can effect kidneys of baby causing increased urine production
what 4 things can result from poly
- maternal abdominal pain
- maternal SOB
- PROM
- preterm delivery
what are two methods of treating poly maternally
- amniocentesis
- drugs like INDOMETHACIN
why is amniocentesis performed and what are the 3 complications
- reduce fluid until largest pocket is less than 8 cm
- PROM, preterm delivery, infection
what does indomethacin do and what is a complication from it when are they administered
- prostaglandin inhibitor which decreases the fetal urine output
- premature closure of ductus arteriosis
- only used early in pregnancy not near term
what are two things proving oligo
- AFI < 5cm
- largest pocket < 2x2cm
how do we calculate first trimester oligohydramnious
5 1/2 - 9 weeks
MSD(mm) - CRL(mm) < 5mm
7 causes of oligo
- PROM
- IUGR
- renal anomaly
- post dates
- abruption
- TTTS (donor twin)
- idiopathic
what three things may result from oligo
- limb anomalies (club feet)
- pulmonary hypoplasia
- restricted growth
