Screening tests In Pregnancy

Pregnancy Wondrous beginning to a glorious motherhood. As the baby is growing in the mother's womb, so grows the responsibility of the mother towards the baby. As the pregnancy keeps progressing through the trimesters of gestation, the health of mother-to-be is noticeable due to the visible signs and symptoms but what remains hidden to the naked eye is the health of the unborn child. Motherhood begins the moment she discovers the news of a new life coming.

First role mother plays is to protect her child from any harm, come what may. But diseases and disorders follow a different rule; they see no age or time. So, what helps to protect from the consequences of disorders are the screening tests that screen the baby and the mother through the use of various markers that will indicate a possible risk. The different pregnancy markers that emerge as oracles of illness are

1. Alpha-Fetoprotein (AFP)
Produced By The Fetus
When to Test Second Trimester
Why to Test Alpha-Fetoprotein test Forewarns and helps to detect the chances of baby having Neural Tube Defects (NTD) or birth defects such as Down syndrome, Trisomy 13 or Trisomy 18.
Sample Maternal blood
Indicators Low value indicates high risks for genetic conditions. Whereas a higher value indicates risk of NTD.

In the fetus, AFP concentration reaches its highest level between 10-13 weeks of gestation. The amount of maternal AFP keeps on increasing throughout the pregnancy, and reaches its peak level around 32 weeks of gestation.

If the fetus is suffering from NTD, high levels of AFP is produced which reaches the amniotic fluid and enters the maternal circulation, thus elevating the level of AFP in the mother's serum too.

Factors Influencing the AFP Levels Multiple pregnancies, singleton pregnancy when the gestation age is estimated incorrectly. The levels of AFP change depending on the age, ethnicity, weight, etc. Other fetal abnormalities which can elevate AFP levels include, kidney diseases, defects of abdominal wall, threatened abortion or still birth, etc.

2. Human Chorionic Gonadotropin (hCG)
Produced By The Placenta
Forms of Hormones Free Beta hCG and Beta hCG

When to Test Free hCG in First Trimester and Beta hCG in Second Trimester.

Why to Test Helps to detect the chances of the fetus having birth defects such as Down syndrome. Also determines ectopic pregnancies and risks of failed pregnancies.

Sample Maternal blood and urine

Indicators High levels of Beta hCG indicate multiple pregnancies, molar pregnancy (genetic errors in fertilization causing growth of abnormal, tissues within the uterus) and Down syndrome. Low level indicate ectopic pregnancy or miscarriage.

Beta hCG helps to keep the pregnancy going, influences fetal development and reaches its peak levels at 10" week of gestation.' Post delivery, Beta hCG levels drop very low in the maternal blood.

Factors influencing the Beta hCG levels Therapeutic abortion, use of heparin and diuretics, etc.

3. Unconjugated Estriol
Produced By The Fetus and the Placenta

When to Test Second Trimester

Why to Test Unconjugated Estriol Helps to detect the chances of baby having inborn defects such as Down syndrome and Edwards syndrome. Also determines defects in pregnancy such as molar pregnancy and still birth.

Sample Maternal blood c

Indicators Low level of estriol serves as a marker for chromosomal aberrations such as Down syndrome, Trisomy 18, NTDs like anencephaly and also indicates fetal demise. Low level of estriol along with relatively normal level of free Beta hCG and AFP may indicate deficiency of key hormones or enzymes. Elevated levels are indicative of pending labor and deficiency of hormones secreted by adrenal glands.

Estriol levels keep on increasing throughout the pregnancy, reaching peak level during the last few weeks before delivery

Factors Influencing Estriol Levels anemia, high blood pressure, reduced liver and kidney functions, or medications such as antibiotics, glucocorticoids, etc.

4. Inhibin A
Produced By The Placenta and Ovaries
When to Test Second Trimester
Why to Test Helps to detect the chances of the baby having genetic defects such as Down syndrome, pregnancy complications such as preeclampsia, miscarriages and fetal growth restrictions.
Sample Maternal blood
Indicators Abnormal level of Inhibin A serves as positive result for birth defects.

During pregnancy, inhibins are produced by the placenta in increasing quantity, reflecting the growth of the fetus.
Factors Influencing Inhibin A levels Smoking, obesity, age, ethnicity, Diabetes, etc.

Increasing risks of genetic diseases and disorders arise due to heredity and other factors such as advancing maternal age, family history, diabetes, viral infections during pregnancy, etc. Pregnancy markers help to determine potential complications, thus helping the parents prepare and plan for the birth.