Chpt 58 Amniotic Fluid...membranes Flashcards
Amniotic fluid is produced by:
Umbilical cord Kidneys Lungs Skin Amniotic membranes
In early gestation, the main source of amniotic fluid is the
Amniotic membrane
In second half of pregnancy, what accounts for nearly all of amniotic fluid
Fetal kidneys and urination
Fetal lung development depends critically on….
The exchange of amniotic fluid within the lungs
Severely low amniotic fluid(lungs) =
Pulmonary hypoplasia
1st trimester fluid can be seen surrounding the fetus…what weeks contain more amounts of fluid?
20-30
Fluid particles within amnion may represent:
Normal variant Particulate matter Vernix(fatty material on fetal skin) Intraamniotic blood Intrauterine meconium(snowstorm)
Intrauterine meconium produces what appearance
Snowstorm
Amniotic sludge Is a dense collection of echogenic particles within the fluid at the level of the
Cervix
Amniotic sludge is associated with
Premature rupture of membranes, chorioamnionitis, preterm delivery
Most common ways to determine level of amniotic fluid
Subjective assessment
Amniotic fluid index—AFI
Single pocket assessment
Performed as the sonographer initially scans through the entire uterus to visually assess the fluid present, fetal position, placental position. Most successful with experienced sonographers(eyeball)
Subjective assessment
Uterine cavity is divided into four quadrants
Largest vertical pocket of amniotic fluid in each quadrant is measured
Amniotic fluid index
For amniotic fluid index the image must be in the ___ plane
Longitudinal
Concerning amniotic fluid index the probe should be in what position when determining fluid pockets
Perpendicular to the table
T/f It is important to apply a lot of pressure when measuring the amniotic fluid index
False it is important to not apply to much pressure causing fluid pockets to appear smaller
Criteria for amniotic fluid index
Image should be in longitudinal plane, probe should be perpendicular to table, measure each pocket in a vertical fashion, do not include thickness of maternal uterine wall, do not apply to much pressure, use color Doppler
A.k.a. maximum vertical pocket
Single pocket assessment
Concerning single pocket assessment fluid should measure greater than
1 cm
Normal values correlate with a total AFI of
10 to 20 cm
AFI less than 5 cm with largest vertical pocket measuring less than 2 cm
Oligohydramnios
AFI measures greater than 24 cm and largest vertical pocket measures more than 8 cm
Polyhydramnios
Horizontal and vertical dimensions of the maximum vertical pocket are multiplied together to obtain a single area
Rarely used, sometimes used with multiple gestation
2 diameter pocket assessment
Twin pregnancies have a ____ median AFI value than singleton pregnancies
Slightly Lower
Polyhydramnios is defined as amniotic fluid volume of
> 2000 ml
Polyhydramnios may be painful, compress other organs, cause __________ or produce shortness of breath from compression on the diaphragm
Hydro nephrosis
Fetal conditions associated with polyhydramnios
Central nervous system disorders (caused depressed swallowing), G.I. problems(ineffective swallowing)
Maternal conditions associated with polyhydramnios
Congestive heart failure, obesity, anemia, Blood incompatibility, diabetes, syphilis
The most common maternal cause of elevated AFI
Diabetes
Fetal causes of polyhydramnios
Meningomyelocele, omphalocele(abdominal wall defect), twin transfusion, hydrocephaly, blood incompatible, skeletal anomalies/sacrococxygeal teratoma, urethra stenosis, spina bifida, esophageal atresia
With polyhydramnios the mother has an increased risk of
Developing pregnancy induced hypertension, preterm labor, postpartum hemorrhage
Oligohydramnios results in fetal crowding and
Decreased fetal movement
Causes of oligohydramnios
Demise, renal anomalies, IUGR, PROM, post dates(42 weeks), pre eclampsia
Most common cause of oligohydramnios
Premature rupture of membranes
Growth delay is increased by how much when oligohydramnios is present
x4
Persistent oligo hydramnios in the ____ has a poor prognosis
Second trimester
Single pocket measurement less than _____ lasting ______ after a spontaneous premature rupture of membranes at ____ gestation is associated with an extremely high mortality rate
<1cm
14 days
<25 weeks
If membranes are not ruptured and oligo is present before 28 weeks gestation careful evaluation of what should be made
Kidneys
When will the fetal membranes normally rupture
After onset of labor
PROM
Premature rupture of membranes
PPROM
Preterm premature rupture of membranes
SPROM
Spontaneous rupture of membranes
Risk factors for rupture of fetal membranes
Smoking, vaginal bleeding, history of STD, PID, pregnancy related invasive procedures, African-American descent
PROM is associated with
Preterm delivery (common)
If PROM occurs at 24 to 33 weeks gestation, follow up procedures include
Administration of corticosteroids, antibiotics, delivery at approximately 34 weeks
An _____ may be performed to verify fetal lung maturity in cases where the fetus needs to be delivered before 34 weeks
Amniocentesis
Term patients who experience rupture of membranes commonly move into active labor within
24 hours
Associated with abnormality in fetal membranes
Common, non-recurrent cause of various fetal malformations involving the limbs, craniofacial region, and trunk
Amniotic band syndrome
Caused by rupture of amnion during early pregnancy development, leading to subsequent entanglement of various fetal parts by fibrous bands, entrapment of fetal parts by the bands may cause lymphedema, amputations, or/defects. with this amnion disruption the fetus may also adhere to and fuse with chorion, causing maldevelopment of fetal tissues
Amniotic band syndrome
Common findings with amniotic band syndrome are
Facial cloths, asymmetric encephaloceles, amputations, club foot deformities
Identified as non-floating bands crossing through the amniotic cavity
Amniotic sheets
Thicker than amniotic bands, Do not cause fetal malformations
Amniotic sheets
Patients with uterine synechia and infertility are diagnosed with
Asherman syndrome
Amniotic sheets are believed to be caused by
Uterine scars(from previous d&c)C-sections, episodes of endometritis
