The various screening and diagnostic tests done during the course of pregnancy play a crucial role in keeping track of the health of both mother and baby and possibly preventing illness and abnormalities in the baby.

First visit to gynaecologist and initial blood tests

Apart from confirmation of the pregnancy, a battery of blood tests is usually done at your first visit to the gynaecologist. The blood is tested for:

    • Blood type, to be prepared in case a blood transfusion is needed
    • The Rhesus (Rh) factor to detect possible incompatibility between the mother and baby’s blood
    • Its haemoglobin level for possible anaemia or low blood iron levels
    • Syphilis, a sexually transmitted disease that could cause abnormalities in the baby
    • HIV, as early detection can enable use of medicine and procedure to prevent HIV from spreading to the baby
    • German measles, as contracting it during pregnancy can cause severe birth defects
    • Any other diseases indicated by the medical history of the mother and/or father.

Scheduled check-ups

During each of your visits to the gynaecologist, the following tests/checks will be carried out:

    • Mother’s weight gain to ensure healthy gain
    • Blood pressure to screen for pregnancy-induced hypertension or preeclampsia
    • Urine will be tested for sugar, protein and blood to detect existing or developing illness or disease related to pregnancy
    • Ultrasound scans will be done to monitor the health and growth of the baby and to check the foetal heartbeat.

Screening and testing for Down’s syndrome and other abnormalities

Screening for Down’s syndrome is usually done between the 11th and 14th week of the pregnancy. It initially involves a simple nuchal scan where the collection of fluid at the back of the baby’s neck is measured during an ultrasound exam – a high reading could indicate Down’s syndrome.

In case of a high reading, this scan could be followed by CVS (chorionic villus sampling) where a sample of cells that line the placenta is extracted, using a fine needle or a catheter, and analysed. The procedure carries a risk of miscarriage of 1%. Amniocentesis is probably the most accurate diagnostic test for Down’s syndrome and involves the extraction of amniotic fluid from the uterus for analysis in a laboratory. Amniocentesis is ideally done between the 16th and 18th week of pregnancy and carries a low 1% risk of miscarriage.

The maternal serum triple test is a blood test that is also used to test for Down’s, but it can also indicate neural tube defects such as spina bifida. It is a blood test that is done between the 15th and 22nd week of pregnancy. The test measures the levels of three hormones, so the correct dating of the test is crucial as incorrect dating can lead to incorrect interpretation of the hormone levels.

 

Sources

 

Murkoff, Heidi E & Eisenberg, Arlene & Hathaway, Sandee. 2002. What to Expect when you’re expecting. Simon & Schuster
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