amniotic fluid ct
TRANSCRIPT
Amniotic fluidPresanted by
Reshma Suzen
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• Amniotic fluid is found in the membranous sac that surrounds the fetus and provides a cushion to protect the fetus
Orgin
Transudation from maternal
circulation
Secretion from amniotic epithelium
Transudation from fetal plasma
Contribution from the fetus
Amniotic fluid volume :
• About 500 mls enter and leave the amniotic sac each hour.
• gradual ↑ up to 36 weeks to around 600 to 1000 ml then↓ after that.
• The normal range is wide but the approximate volumes are:
- 50 ml at 12 weeks
- 400 ml at 20 weeks
- 800 ml at 34 weeks.
- 1L at 36-38 week.
- 600 - 800 ml at term.
compositiona) Organic @ non organic Protein : .3gm % Glucose : 20mg% Urea : 30mg% NPN : 30mg% Uric acid : 4mg% Creatine : 2mg Total lipids : 50mg% hormones
b) Non organic Sodium Sodium chloridec) Suspended particles Lanugo Exfoliate squamous cell Vernix caseosa
Physical features Alkaline Low specific gravity – 1.010 Hypotonic to maternal serum at term Osmolarity – 250 Osmol Colour – in early pregnancy
colourless - at term it become pale
straw colored
Abnormal color Green : meconium stained Golden : Rh incompactability Greenish yellow : post maturity Dark colured : concealed accidental
haemorrhage Dark brown : IUD
Amniotic fluid function:
During pregnancy• Allow room for fetal growth, movement
and development.
• Ingestion into GIT→ growth and maturation.
• Fetal pulmonary development (20 weeks).
• Protects the fetus from trauma.
• Maintains temperature.
• Contains antibacterial activity.
During labor
Dilatation of cervix
Flushes the birth canal by its
antiseptic and bactericidal action
Clinical importance of AF:
• Screening for fetal malformation (serum α-fetoprotien).
• Assessment of fetal well-being (amniotic fluid index).
• Assessment of fetal lung maturity (L/S ratio).
• Diagnosis and follow up of labour.• Diagnosis of PROM
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Tests for the Well-being and Maturity
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Test Normal values at term Significance
__________________________________________________________
Bilirubin scan 0.025 mg/dl Hemolytic disease
of the newborn
L/S ratio 2.0 Fetal lung maturity
Phosphatidyl- Present Fetal lung maturity
Glycerol
Creatinine 1.3 – 4.0 mg/dl Fetal age
Alpha fetal protein 4.0 mg/dl Neural tube disorders
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Amniotic fluid abnormalities
Oligohydramnios: Defined as reduced amniotic fluid i.e.
amniotic fluid index of 8 cm
Polyhydramnios: Defined as excessive amount of amniotic fluid
of 2000 ml or more (AFI of > 20 cm