Amniotic fluid -BIOCHEMICAL ANALYSIS for undergraduate medical students

1. Amniotic fluid analysis
Dr Rohini C Sane
Professor
Department of Biochemistry
DY Patil Medical College ,EBENE

2. Amniotic fluid analysis
• Liquid produced by membranes & fetus
• Surrounds the fetus throughout pregnancy
• Volume –increases with gestational age( 2weeks –30ml to 350ml
(20weeks )---thereafter 500-1000ml
• Clear with some desquamated fetal cells & little lipid

3. Functions of Amniotic fluid
• It provides physical protection
• Medium for exchange of various chemicals

4. Diagnostic importance of amniotic fluid
• AMNIOCENTESIS –PROCESS BY WHICH AMNIOTIC FLUID COLLECTED FOR
ANALYSIS
• Assessment of fetal maturity—cytological staining of fat cells
Estimation of creatinine concentration - >1.6mg /dl indicates fetal
maturity
Lung maturity –lecithin –sphingomyelin (l/s) ratio > 2:1 or more indicates
normal Lung maturity
lecithin –sphingomyelin (l/s) ratio < 2:1 Lung immature
Delay induced delivery till Lung mature
INDEX OF SURFACTANT –(SURFACE LOWERING COMPLEX)
PREGNANCY ----CELLS LINING ALVEOLI START SYNTHESIZING DIPALMIOTYL
LECITHIN,AS LUNG MATURE L/S RATIO INCREASES

5. EARLY GESTATION PRE TERM
VLOUME 450-1200 ML 500-1400ML
BILIRUBIN < 0.O75 MG/ML < 0.O25 MG/ML
CREATININE 0.8—1.1 MG/DL 1.8-4.0 MG/DL
ESTIROL 10 MICROGRAM /DL >60 MICROGRAM /DL
LECITHIN –
SPHINGOMYLIN RATIO
< 1:1 > 2:1
PROTEIN 0.6 -0.24 GM/DL 0.26 -0.19 GM/DL
UREA 18+6MG/DL 30+11MG/DL
URIC ACID 3.7+1 MG/DL 9.9 +2.2 MG/DL

6. Diagnostic importance of amniotic fluid
• Diagnosis of congenital disorder
• prenatal diagnosis
Chromosomal disorder Down”s syndrome
Metabolic disorder Cystic fibrosis
Sex linked disorder Haemophillia
Enzyme defect Tay sach”s disease

7. Diagnostic importance of amniotic fluid
• 22-24 WKS OF GESTATION –ESTIMATION OF CHOLINE ESTERASE
ISOENZYME ---NEURAL TUBE DEFECTS
• PHENYL ALANINE –PHENYL KETONURIA
• METHYL MALONIC ACID –VITAMIN B12 DEFICIECY –INBORN DEFECT
ODD CHAIN FATTY ACID)VALINE,ISOLEUCINE,THREONINE

8. Diagnostic importance of amniotic fluid
• ASSESSMENT OF HEMOLYTIC DISEASE—ESTIMATION OF BILIRUBIN TO EVALUATE
SEVERITY OF HEMOLYTIC DISEASE
• MEASUREMENT OF ALPHA FETO PROTEIN –(AFP)
• NORMAL ---15-40 MICROGRAMS /ML
• < 1.0 MICROGRAMS /ML AT 40WEEKS OF GESTATION ---NEURAL TUBE
DEFECT,FETAL DISTRESS ,TURNER”S SYNDROME

9. Google image

12. Google image

13. Google image