Amniotic fluid is the fluid surrounding the fetus within the amniotic sac. It serves several important functions, including allowing room for fetal growth and movement, ingestion for development, and protecting the fetus from trauma. Abnormal amounts of amniotic fluid can be diagnosed through ultrasound measurement of the amniotic fluid index or deepest vertical pool. Polyhydramnios, an excessive amount of fluid, can cause complications for both mother and fetus like preterm delivery. Oligohydramnios, a deficiency of fluid, increases risks like fetal distress, deformities, and malformations. Management depends on the cause, gestational age, severity, and fetal well-being and may include increased monitoring, induction of
2. DEFINITION
• Amniotic Fluid is that fluid surrounding the
developing fetus,found within the amniotic sac
• Physical characteristics:
It is clear pale yellow fluid. pH of is around 7.2.-Specific
gravity of 1.0069 – 1.008.
• Composition of amniotic fluid
98% water, 2% solid substances like inorganic & organic salts,
fetal epithelium, protein & enzymes.
3. Following forms the amniotic fluid:
• 1- Amniotic membrane
• 2- Maternal tissue (interstitial) fluid by
diffusion across the amnio-chorionic
membrane from the deciduas parietalis.
• 3- Filtrated from maternal blood.
• 4- Fluid is also secreted by the fetal respiratory tract (300 –
400 ml daily) and enters the amniotic cavity.
• 5-Fetal urine.
4. AMNIOTIC FLUID CIRCULATION
• About 500mls 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: -
500 ml at 18 weeks
800 ml at 34 weeks.
600 ml at term.
5. AMNIOTIC FLUID FUNCTION:
• 1. Allow room for fetal growth,movement and development.
• 2. Ingestion into GIT→ growth and maturation.
• 3. Fetal pulmonary development (20 weeks).
• 4. Protects the fetus from trauma.
• 5. Maintains temperature.
• 6. Contains antibacterial activity.
• 7. Aids dilatation of the cervix during labour.
6. CLINICAL IMPORTANCE OF AF:
• 1. Screening for fetal malformation (serum α- fetoprotien).
• 2. Assessment of fetal well-being (amniotic fluid index).
• 3. Assessment of fetal lung maturity (L/S ratio).
• 4. Diagnosis and follow up of labour.
• 5. Diagnosis of PROM (ferning test).
7. AMNIOTIC FLUID VOLUME ASSESSMENT
• Clinical assessment is unreliable.
• Objective assessment depends
on U/S to measure: 1.Deepest
vertical pool (DVP).
2.Amniotic fluid index (AFI).
It is a total of the DVPs in each
four quadrants of the uterus. it is a
more sensitive indicator of AFV
throughout pregnancy.
8. AMNIOTIC FLUID ABNORMALITIES
• Oligohydramnios:
Defined as reduced amniotic fluid i.e.
amniotic fluid index of 5 cm or less or the
deepest vertical pool <2cm.
• Polyhydramnios:
Defined as excessive amount of amniotic
fluid of 2000 ml or more AFI of > 25 cm or
the deepest vertical pool of > 8 cm) .
14. COMPLICATIONS
Fetus
• Fetal prognosis worsens with more severe
hydramnios and congenital anomalies
• 15-20% fetal malformations
• Preterm delivery
• Suspect diabetes
• Prolapse of cord
• Abruption
Mother
• Placental abruption
• Uterine dysfunction
• Post-partum hemorrhage
• Abnormal presentation –C/S
15. TREATMENT
• Mild to Moderate hydramnios: rarely
requires treatment
• Hospitalization, bed rest
• Amniocentesis
• NSAIDs
• Blood sugar control
Indomethacin therapy:
impairs lung liquid production/enhances absorption.
↓fluid movement across fetal membranes.
Complications:
premature closure of ductus arteriosus
impairment of renal function, and cerebral vasoconstriction.
NOT USED AFTER 34 WKS
17. DIAGNOSIS
• SYMPTOMS SIGNS
NOT SPECIFIC
H/O leaking
Post term
s/o preeclampsia
Drugs
Less fetal movements
• EXAMINATION
Uterus – small for date
Feels full of fetus
Malpresentations
IUGR