Dr Karuna Raja

Antenatal testing

Following is a list of suggested tests. Dr. Raja will guide you on the recommended antenatal tests, the reason for testing and the timing of the tests.

Antenatal Tests at the time of booking

  • Full Blood Count - to check for anaemia
  • Screening for Thalassemia
  • Blood Group
  • Antibody
  • Rubella Testing - to check for immunity to German Measles
  • HIV
  • Hepatitis B and C
  • VDRL  - to check for syphilis
  • Mid Stream Urine  - to check for silent urinary infections
  • Varicella Zoster (chicken pox)
  • Screening for Cystic Fibrosis (not routinely preformed, but will be preformed at request or if there is a family history of cystic fibrosis disease or carrier state)
  • Vaginal Swab in Early Pregnancy - to exclude bacterial vaginosis in some women with risk factors (i.e: previous premature delivery)
  • Thyroid function tests

Some women will need to have a  glucose tolerance test at the time of booking, if they have risk factors for developing diabetes in pregnancy (i.e: family history, diabetes in previous pregnancy, etc).

 

Disorders Detected by DNA Technology

  • Duchenne and Becker Muscular Dystrophy
  • Myotonic Dystrophy
  • Fragile X
  • Haemoglobinopathies (e.i: alpha and beta thalassemia and sickle cell disease)
  • Haemophilia A and B
  • Huntington Disease
  • Cystic Fibrosis
  • Neurological Diseases (i.e: neurofibromatosis, peroneal muscular dystrophy, type la and
    muscular atrophy)
  • Adult Polycystic Kidney Disease

Please discuss with me or with your GP very early in pregnancy if there is any history of any of these disorders in your or your partner’s family.

 

Tests between 11 - 13 Weeks

  • Nuchal Translucency test/serum screening and genetic counseling - you may be offered genetic counseling if it is considered that your baby is at an increased risk of chromosomal abnormalities (i.e: family history or if you are over 34 years of age).

Although the risk of chromosomal problems in babies increased with increasing maternal age and more so after 34-35 years of age, this practice offers first trimester screening tests to all pregnant women. An ultra sound is preformed between 11.5 - 13.5 weeks to measure the thickness of skin at the back of the baby’s neck (NT). It is a screening test for Down Syndrome and other chromosomal disorders the baby may have. this is preformed by a specialist in woman ultrasounds and is non-invasive. As it is a screening test only, the accuracy is only about 70%.

A combined first trimester blood (maternal) and Nuchal Translucency test is available to increase the accuracy (up to 90%) of the estimation of risk of chromosomal problems. It consists of a blood test on you at around 12 weeks gestation, followed by a baby ultrasound. A combined risk is then calculated taking into account the maternal age.

 

Tests between 18 - 19 Weeks

  • Foetal Anomaly Scan

A detailed ultrasound examination of your baby is preformed to detect any structural abnormalities. You will be given a photograph of the baby or you may request a CD.

 

26 - 28 Weeks

  • Full Blood Count
  • Antibody Screening
  • Short (1 hour) or Full (2 hour) Glucose Tolerance Test - The Glucose Tolerance Test is a routine screening test to detect pregnancy induced (gestational) diabetes. You will be asked to drink a glucose solution and a blood test will be taken an hour later. If the results are abnormal, you will be asked to have a Full Glucose Tolerance Test, which takes about two hours and needs formal booking. Some women have a full GTT at 28 weeks even if they have had a ha full test early in pregnancy.
  • Vaginal Swab - to check for any infections, specifically Strep B, which you may carry (30% of Australian women carry this bacteria in their vagina without having any adverse effects). Strep B can be harmful to the baby if appropriate measures are not taken during the delivery (most commonly antibiotics to kill the bacteria at the time of vaginal delivery). In case of previous mid-trimester miscarriages or a premature delivery, a vaginal swab may also be preformed early in pregnancy.

All results of these screenings will be discussed at the next visit. Should there be a problem with any of your results you will be contacted earlier.

 

Specialized Tests

  • Chorionic Villous Sampling (CVS) - Chorionic villi are small thread like projections that make up part of the early placenta. Cells of the placenta are very similar in chromosomal structure to the foetus and so abnormalities in the chromosomes of chorionic villi are also found in the chromosomes of the baby. During the procedure, a small amount of placental tissues is removed through the vagina and cells are examined for chromosomal abnormalities. This text can be preformed from 10 weeks gestation and onwards. The results are usually available in 2 weeks. This is an invasive test with risks of infection and miscarriage. You would have extensive pre-test counseling if you are recommended to have this test.
  • Amniocentesis - This test provides information about chromosomal structure of the baby and is preformed at 15 weeks gestation and onwards. It involves removing a small amount of amniotic fluid (water around the baby) which is contains baby cells that have shed from the skin, lungs and bladder of the baby. The results are available in approximately 2-3 weeks. There is a small risk of miscarriage and infection with this tests.

Based on your age, family history and/or abnormal first trimester screening (nuchal translucency and blood tests) it may be necessary to have more detailed testing such as Amniocentesis and CVS performed. An ultrasound examination is done before preforming these tests. Both testes are preformed by specialist doctors.

The risk of miscarriage with Amniocentesis is less than one loss of pregnancy every 200 women tested. The risk of miscarriage is slightly higher with CVS. Leaking of amniotic fluid (ruptured membrane), as well as infection can occur after both these procedures. Sometimes the results could be incorrect due to the sample growing mother’s cels rather than foetal cells.

Additional ultrasounds may be needed to check the baby’s growth and well-being, liquor volume or length of cervix or placental location.

 

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