BIOCHEMICAL TEST

INTRODUCTION

Prenatal diagnosis or prenatal screening is testing for diseases or conditions in a fetus or embryo before it is born.

Congenital anomalies account for 20 to 25% of perinatal deaths.

Diagnostic prenatal testing can be by invasive or non-invasive methods.

USE

Managing the remaining weeks of the pregnancy

Determining the outcome of the pregnancy Planning for possible complications with the

birth process Planning for problems that may occur in the

newborn infant Deciding whether to continue the pregnancy Finding conditions that may affect future

pregnancies

PURPOSES OF PRENATAL DIAGNOSIS

To enables timely medical or surgical treatment of a condition before or after birth.

To give the parents the chance to abort a fetus with the diagnosed condition.

To give parents the chance to "prepare" psychologically, socially, financially, and medically for a baby with a health problem or disability, or for the likelihood of a stillbirth.

INDICATION

Women over the age of 35 Women who have previously had premature

babies or babies with a birth defect, especially heart or genetic problems

Women who have high blood pressure, diabetes, asthma, or epilepsy

Women who have family histories or ethnic backgrounds prone to genetic disorders, or whose partners have these

Women who are pregnant with multiples (twins or more)

Women who have previously had miscarriages

MATERNAL SERUM ALPHA-FETOPROTEIN (MSAFP)

INTRODUCTION

Alpha-fetoprotein (AFP) is a protein that is normally produced by the fetus' liver.

AFP is present in the fluid around the fetus (amniotic fluid).

This test is performed between weeks 15 and 20 of a pregnancy.

  PROCEDURE

The AFP test involves taking a blood sample. Blood is drawn from a vein (venipuncture),

usually from the inside of the elbow or the back of the hand.

RISKS

Excessive bleeding. Fainting or feeling lightheaded. Hematoma (blood accumulating under the

skin). Infection (a slight risk any time the skin is

broken). Multiple punctures to locate veins.

RESULT

Normal AFP levels for non-pregnant women are less than 300 nanograms per milliliter.

Greater-than-normal levels of AFP in men and non-pregnant women may indicate:

Cancer in testes, ovaries, stomach, or pancreas

Cirrhosis of the liver Liver cancer Malignant teratoma

During pregnancy, increased levels of AFP may indicate:

Fetal defects Spina bifida Anencephaly Omphalocele Tetralogy of Fallot Duodenal atresia Turner's syndrome

Wrong gestational age Open nural tube defect Multiple pregnancy Intrauterine fetal death Renal abnormalities Anterior abdominal wall defects

TRIPLE TEST

INTRODUCTION

Also Known As, Multiple Marker Screening. The triple screen test is performed between

the 15th and 20th week of pregnancy although results obtained in the 16th -18th week are said to be the most accurate.

The triple screen test is a maternal blood screening test that looks for three specific substances:

AFP hCG and Estriol

The triple test measures,

AFP:- alpha-fetoprotein is a protein that is produced by the fetus.

hCG:- human chorionic gonadotropin is a hormone produced within the placenta

Estriol:- estriol is an estrogen produced by both the fetus and the placenta

INDICATIONS Have a family history of birth defects Age 35 years or older Used possible harmful medications or drugs

during pregnancy Have diabetes and use insulin Had a viral infection during pregnancy Have been exposed to high levels of

radiation

Low levels of AFP may indicate increased risk for,

Trisomy 18Down Syndrome

High levels of AFP may indicate increased risk for,

Open Nural Tube DefectIUGRStill BirthPrematureMultiple Gestation

PROCEDURE

Triple test is a screening test and not a diagnostic test.

The triple screen test involves drawing blood from the mother which takes about 5 to 10 minutes.

The blood sample is then sent to the laboratory for testing.

The results usually take a few days to receive.

AMNIOCENTESIS

PROCEDURE

Inform mother about a procedure. Emptying the bladder. Proper position is given. A local anesthesia can be given to the

mother. A needle is usually inserted through the

mothers abdominal wall, then through the wall of the uterus and finally in to the amniotic sac.

With the aid of ultrasound guidance. Aspirate approximately ,20 ml.

AFTER CARE

Doctors recommend client to rest and avoid physical strain (such as lifting) after amniocentesis.

Test results are generally available in two to three weeks.

COMPLICATION

CORDOCENTESIS

INTRODUCTION

Percutaneous umbilical cord blood sampling (PUBS), also called cordocentesis.

This test carries a significant risk of complication and is typically reserved for pregnancies determined to be at high risk for genetic defect.

It is performed at 18 weeks' gestation.

PROCEDURE

This procedure can also be used to check if baby has anemia.

If baby has severe anemia, health care provider can immediately give baby a blood transfusion.

Guided by ultrasound, doctor pinpoints the spot where the umbilical cord meets the placenta.

He then inserts a needle through abdomen and uterus and into the umbilical cord and withdraws a small amount of fetal blood.

There are two routes for retrieving fetal blood.

CORDOCENTESIS DETECTS ,

Chromosome abnormalities Blood disorders Malformations of the fetus Fetal infection (i.e. toxoplasmosis or rubella) Fetal platelet count in the mother Fetal anemia

RISK

Blood loss from the puncture site Infection Drop in fetal heart rate Premature rupture of membrane Fever Chills Leaking of amniotic fluid

CHORIONIC VILLUS SAMPLING

INTRODUCTION

Chorionic villus sampling (CVS), sometimes misspelled “chorionic villous sampling”.

CVS usually takes place at 10–12 weeks' gestation.

This procedure is mostly associated with testing for Down syndrome.

INDICATION

Abnormal first trimester screen results Increased abnormal ultrasound findings Family history of a chromosomal abnormality

 or other genetic disorder Parents are known carriers for a 

genetic disorder Advanced maternal age (maternal age above

35).

PROCEDURE

Patient may be asked to drink a glass of fluid about an hour before the test.

Be sure to tell your doctor if you are allergic to any medicines.

Transabdominal (through the belly) chorionic villus sampling or transcervical (through the cervix) chorionic villus sampling can be done.

The choice may depend on where the fetus and placenta are in the uterus.

 THROUGH THE BELLY (TRANSABDOMINAL)

Client will lie on your back on an examination table.

Gel or oil will be rubbed on your belly to use with the ultrasound unit.

Doctor then puts a long thin needle through your belly and uterus to the placenta and collects a sample of the chorionic villus cells.

After the sample is collected, your doctor may listen to baby’s heart rate and check your blood pressure, pulse, and breathing.

THROUGH THE CERVIX (TRANSCERVICAL)

Client will be asked to take off clothes below the waist and drape covering around your waist.

Client will then lie on back on an examination table.

Doctor will put an instrument with curved sides (speculum) into vagina.

The cervix will be cleaned with a special soap.

An ultrasound will be used to help doctor guide the catheter through cervix to the placenta.

When the catheter is correctly placed, a sample of chorionic villus cells will be collected.

AFTER THE PROCEDURE

It is normal to have mild cramping, leakage of a small amount amniotic fluid, and vaginal spotting for the first day or two after the procedure.

Moderate or severe belly pain or cramping. More leakage of amniotic fluid from your

vagina. More vaginal bleeding than spotting or bright

red bleeding. Chills or a fever. Dizziness. Redness or swelling at the needle site.

RESULT

Normal: No abnormalities are found in the genetic

material of the chorionic villus cells.

Abnormal:Abnormalities are found in the genetic material

of the chorionic villus cells.