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It is a pretty useful pregnancy screening test to determine the healthy development of the foetus, and as such this test should not be ignored. It is generally done alongwith ultrasound scan. It is typically done in first trimester of pregnancy. Following conditions can be diagnosed with this test:

• assessing whether the unborn baby is at risk for any mental disorder
• It is used primarily for the detection of Down syndrome
• also helps to detect Trisomy 18, that results in mental retardation and severe birth defects
• It also helps in the detection of Trisomy 21.T, which cause mental disorders, heart disorders and other health conditions affecting vital organs

Ideally all women are advised for this test in first trimester of their pregnancy.

The test is recommended for women who:

• 35 years old or older
• have a family history of birth defects
• have diabetes and use insulin

Other  names: Double Marker test, MSS test

The maternal serum screening test is a blood test offered to pregnant women.It helps to inform them of the chance of their unborn child having Down syndrome, Edward syndrome or a neural tube defect.

Maternal serum screening may be done in the first trimester of pregnancy, when it is combined with an ultrasound. This is called the combined first trimester screening test. Or, testing may be performed in the second trimester of pregnancy. This is called the second trimester maternal serum screening test. 

This test measures the amounts of following substances

• Beta HCG: A hormone produced by the placenta. Low levels may indicate potential problems with the pregnancy, including possible miscarriage or ectopic pregnancy. High levels of HGC can indicate a molar pregnancy, or a multiple pregnancy with two or more children.
• Pregnancy-Associated Plasma Protein A (PAPP-A): it is a protein produced by the placenta. Abnormal PAPP A levels not only indicates complications in pregnancy but also suggest possibility of certain genetic disorders. Lower the level of PAPP found greater are the chances of abnormality.

One in twenty pregnancies could have birth defects. Some couples have a much greater risk of having baby with birth defects than the other.However, blood levels alone don’t produce your results. Instead, the blood test is used along with an ultrasound called a nuchal translucency (NT) scan, which examines the clear tissue at the back of your baby’s neck.

Requirements: there are no special precautions required before you take the test. There are no risk associated with maternal screening Test.

Normal results:

hCG	20,000 to 200,000 IU/L
PAPP A	>=0.5

Interpretation:

Results are obtained as positive or negative. However, only blood reports are not sufficient to infer the diagnosis. An ultrasound scan is also done along with blood report. A positive result means pregnancy in high risk category and thus requires close monitoring. However, factors such as mother’s age and age of developing fetus, family history are also considered before interpreting the results. Hence, you should consult your doctor to understand your risk and options.