Biochemical parameters

MHR DAV

1. PRESENTED TO: dr. babaldeep kaur ASST. PROFESSOR PRESENTED BY: MRS POOJA SINGH MSC NURSING 1 ST YEAR BIOCHEMICAL PARAMETERS

2. BIOCHEMICAL PARAMETERS These are some investigations which are done during pregnancy to rule out any kind of congenital abnormality, chromosomal abnormality, sex linked genetic disorder or inborn errors of metabolism.

3. Cont… There are number of tests which are:- Maternal serum Alfa fetoprotein Triple test Acetyl choline esterase Amniocentesis Chorionic villus sampling Cordocentesis

4. 1. MATERNAL SERUM ALPHA FETOPROTEIN MSAFP is a screening test that examines the level of alpha-protein in the mother's blood during pregnancy. Alfa-fetoprotein is a oncofetal protein which is produced by yolk sac and fetal liver. The highest level of AFP in fetal serum and amniotic fluid is reached around 13 weeks and thereafter it decreases. Maternal serum level reaches a peak around 32 weeks.

5. Cont… Maternal serum alpha protein is elevated in a number of conditions like Wrong gestational age Open neural tube defect Renal anomalies Multiple pregnancy IUFD Low levels are found in trisomies (Down syndrome).

6. INDICATIONS OF MSAFP SCREENING Women who have a family history of birth defects. Women who are 35 years or older. Women who used possible harmful medications or drugs during pregnancy. Women who have diabetes.

7. CONT… Time of performing test: - 15-18 weeks. PROCEDURE:- Alfa-fetoprotein is a oncofetal protein which is produced by yolk sac and fetal liver.

8. 2. TRIPLE TEST It is a combined biochemical test which include MSAFP, HCG and unconjugated estriol. It is used for detection of Down syndrome. In an affected pregnancy level of MSAFP and UE3 tend to be low while that of hCG is high.

9. CONT… Time of performing test: - Between 15th and 18th week of gestation. INDICATION:- Women who have a family history of down syndrome Women who are 35 years or older Women who used possible harmful medications or drugs during pregnancy

10. CONT… PROCEDURE:- The triple screen test involves drawing blood from the mother. The blood sample is then sent to laboratory for testing. AFP is produced in the yolk sac and fetal liver.

11. 3. ACETYL CHOLINE ESTERASE (ACHE ) Amniotic fluid acetyl choline esterase level is elevated in most cases of open neural tube defects. It has got better diagnostic value than AFP. Time of performing test :- Between 15th and 18th week of gestation.

12. CONT… INDICATION:- Women who have a family history of open neural tube defect. Women who are 35 years or older PROCEDURE :- AFP testing is the sequence of tests. The first-two are of maternal serum and the final test of amniotic fluid. An Elevated AFP Level is indicative of significant fetal pathology. A low level of AFP may be associated with Down syndrome. The Normal AFP concentration in liquor amnii at the 16th week is about 20mg/L.

13. 4 . AMNIOCENTESIS   It is an invasive procedure and is performed only when the necessary information cannot be obtained by other non-invasive procedures like ultrasound scanning .

14. Cont… Amniocentesis is a prenatal test in which a small amount of amniotic fluid is removed from the sac surrounding the fetus for testing.

15. TIMING / INDICATION Early months 14 to 16 weeks Pregnancy is above the age of 35 years A previous child born with chromosomal abnormalities, particularly autosomal trisomy For diagnosis of chromosomal and genetic disorders . Sex –linked disorders . Inborn errors of metabolism Neural tube defects

16. CONT… PROCEDURE:- Removal of up to 20 ml of the amniotic fluid from the pregnant women, using a 22G spinal needle.

17. 5. CHORIONIC VILLUS SAMPLING This procedure is performed in specialised centres, for prenatal diagnosis of genetic disorders. It is carried out transcervically between 10-12 weeks and transabdominally from 10 weeks to term. Diagnosis can be obtained by 24 hours and as such, if termination is contemplated, it can be done in the first trimester safely.

18. Cont… A few villi are collected from the chorion frondosum under ultrasonic guidance with help of a long malleable plastic catheter introduced transcervically along the extraovular space. When it provides earlier diagnosis than amniotic fluid studies, complications like fetal loss.

19. 6. CORDOCENTESIS A 25 gauze spinal needle 13cm in length is inserted through the maternal abdominal and uterine wall under real time ultrasound guidance using a curvilinear probe. The needle tip is progressed carefully and it punctures the umbilical vein approximately 1-2 cm from the placental insertion. Generally 0.5 to 2ml of fetal blood is collected. It is performed under local anaesthetic usually after 18weeks of gestation.