Information and Support for Prenatal Screening

Diagnoses

  • Down syndrome is a condition that is physically characterised by features such as a flatter face and wider neck than usual, small ears and upward slanting eyes. As a baby, they often have low muscle tone, and can seem floppy. Individuals with Down syndrome have an extra copy of the chromosome number 21 (3 copies instead of the usual 2 copies). Down syndrome is present in 1 in every 1000 births. The risk of Down syndrome can be detected at the combined first trimester screening with Nuchal Translucency scan, or non-invasive prenatal testing (NIPT). Tests such as amniocentesis and CVS confirm the diagnosis. There can be physical problems associated with the condition, involving the digestive system, heart and overall development. Intellectual disability is a feature of Down Syndrome, but the severity varies between individuals. There is currently no treatment available for the condition, but associated problems can be managed. Interventions can also be helpful in maximising learning and social potential. No two people with Down Syndrome are alike, and there is no way of predicting the level of impairment a baby with Down Syndrome will go on to experience. The degree of support that an individual with Down Syndrome will need to live an independent life will vary from very little, to complete dependence. Further information about Down Syndrome can be accessed at Down Syndrome Australia (https://www.downsyndrome.org.au/index.html). Online support forums for parents of children with Down Syndrome can also be helpful in understanding the varied lived experiences of individuals with Down Syndrome, such as Josee's Journey of Faith Hope & Love (https://www.facebook.com/JoseeFaithHopeLove/).

  • Edwards syndrome is a chromosomal abnormality, where an extra copy of chromosome 18 is present. There are three types of Edwards Syndrome: Complete Trisomy 18 (there are 3 copies of chromosome 18), Mosaic Trisomy 18 (there is a mixture of 3 and 2 copies of chromosome 18), and Partial Trisomy 18 (there is an extra part of chromosome 18 in all cells). Edwards syndrome is present in 3 in every 10 000 births. The risk of T18 can be detected by combined first trimester screening with Nuchal Translucency scan, or non-invasive prenatal testing (NIPT). Tests such as amniocentesis and CVS confirm diagnosis. There is unfortunately currently no treatment available for the condition.

    The outlook for your baby depends on the type of T18 (see above):

    Complete

    Babies with complete T18 usually do not survive pregnancy or pass away soon after birth.

    Mosaic and Partial

    Babies with Mosaic or Partial T18 can sometimes live beyond a year but this is rare.

    There is no way to predict the severity of these abnormalities prior to birth, but if the baby does survive, management of infections, abnormalities and feeding can keep the baby as comfortable as possible.

  • Patau syndrome is a chromosomal abnormality where there is an extra copy of the chromosome 13 present. There are three types of Patau Syndrome: Complete Trisomy 13 (there are 3 copies of chromosome 13), Mosaic Trisomy 13 (there is a mixture of 3 and 2 copies of chromosome 13), and Partial Trisomy 13 (there is an extra part of chromosome 13 in all cells). Patau syndrome is present in 2 in every 10 000 births. The risk of Patau syndrome is detected at the combined first trimester screening with Nuchal Translucency scan, or non-invasive prenatal testing (NIPT). Diagnosis is confirmed via amniocentesis or Chorionic Villus Sampling (CVS). Unfortunately, there is currently no treatment for Patau Syndrome.

    The outlook for babies with Patau Syndrome depends on the type (see above):

    Complete

    Babies with Complete T13 usually do not survive pregnancy or pass away soon after birth.

    Mosaic and Partial

    Babies with Mosaic or Partial Patau’s Syndrome can survive to adulthood but this is rare.

    Problems associated with Trisomy 13 include: major brain abnormalities, cleft lip/palate, heart problems, partially developed eyes and ears, and difficulties with their arms and legs.

    Unfortunately, there is no way to predict the severity of these abnormalities prior to birth.

  • In HPE, the front part of the brain does not successfully separate during development in to left and right halves. HPE is usually detected at the fetal anomaly scan (occasionally it can be seen on the 12-week scan but not before). HPE is present in 1 of 7500 births. The cause of HPE is unknown. HPE can involve excess fluid in the brain, problems with organs, smaller head, cleft lip, and epilepsy. Unfortunately, problems can be severe, and brain function can be severely impacted. Unfortunately, there is currently no treatment for this condition. Sadly, of the babies with HPE, only 3% survive to birth. If this happens the baby is unfortunately very unlikely to survive past 6 months of age.

  • Anencephaly is a neural tube defect, which describes when the brain or spinal cord do not develop properly. As the skull does not develop properly, this can lead to damage to the baby’s brain. Anencephaly is present in 6 of every 10 000 births. Anencephaly is detected at the first trimester scan, or fetal anomaly scan. A second scan may be needed to confirm diagnosis. There is currently no treatment for this condition. Sadly, babies with Anencephaly do not survive pregnancy or pass away very soon after birth. In rare cases, the baby may live for a few days.

  • Open Spina Bifida is a neural tube defect, which describes when the brain or spinal cord do not develop properly. As the baby’s brain and the spinal column do not develop properly, there is an opening in the baby’s spine where spinal fluid escapes. Additionally, 70% of babies with this condition also present with hydrocephalus (this refers to excess cerebrospinal fluid in the brain). Open spina bifida is present in 6 of every 10 000 births. This condition is detected at the fetal anomaly scan. A second scan may be needed to confirm diagnosis. Treatment can involve surgery after birth, but this depends on the location and severity of the hole. If hydrocephalus is also present, then surgery to reduce the fluid in the brain could be necessary. Mild cases can be absent of major problems. Problems associated with this condition can include difficulty controlling the bowels and bladder, and difficulty walking. Hydrocephalus can lead to learning difficulties.

  • In CDH the baby’s diaphragm does not develop properly. Sometimes the baby’s organs can shift through a hole in the diaphragm and occupies the space that lungs need to grow into. Consequently, the lungs can fail to develop properly. CDH is present in 4 of every 10 000 births. It can be detected on the fetal anomaly scan, at a later scan, or after birth. Treatment for this CDH involves immediate medical attention post-birth. Breathing equipment will likely be used to help the baby breath while his or her lungs become stronger. Surgery can repair the hole in the diaphragm if the baby is suitable for surgery. The outlook for this condition is that 5 in 10 babies with CDH survive. This depends on how big and strong the lungs have become. In 1 in 10 babies with CDH, they will also have heart or chromosomal abnormalities.

  • In Gastroschisis the baby’s abdomen doesn’t develop properly. Due to a hole in the abdominal wall, the baby’s intestines can grow through the hole. Gastroschisis is present in 5 of every 10 000 births. Gastroschisis is detected on the fetal anomaly scan (occasionally it can be seen on the 12-week scan but not before). Further scans may be needed to confirm diagnosis. Babies with this condition can often be born prematurely. Unfortunately, 100% of babies with this condition need surgery. However, 90% of babies with this condition make a full recovery after surgery. Digestion of milk can be difficult for the first 2-4 weeks after surgery, but this can be managed and will settle.

  • In Exomphalos, the baby’s abdomen doesn’t develop properly. The abdominal wall does not successfully join together at the place of the umbilical cord. Through this hole, intestines (and sometimes other organs) can develop outside of the abdomen. Exomphalos is present in 4 of every 10 000 births. Exomphalos is detected at the fetal anomaly scan (occasionally it can be seen on the 12-week scan but not before). A second scan will be needed to confirm diagnosis. Unfortunately, 100% of babies born with this condition require a surgery. Additionally, 80% of babies with this condition also have chromosomal or heart abnormalities. Outlook for a baby with Exomphalos can vary. If the baby only presents with Exomphalos then there is 90% chance of survival following surgery. If the baby has additional chromosomal or heart abnormalities, it’s possible that survival rate can be 10% (depending on the severity of the additional abnormalities).

  • Congenital Heart Disease describes abnormalities of the heart. There are three types: structural abnormalities, functional abnormalities, and problems with the rhythm of the heart. These abnormalities all vary in complexity and severity. Congenital heart disease is present in 35 of every 10 000 births. Congenitial Heart Disease is often detected at the fetal anomaly scan (occasionally it can be seen on the 12-week scan). A second scan is usually needed to confirm diagnosis. However, sometimes it is not picked up before birth. If Congenital Heart Disease is detected, then a referral is made to a specialist. Options for treatment vary in availability and type.

  • Bilateral Renal Agenesis means that the baby does not have kidneys. The baby’s kidneys help to create amniotic fluid (the fluid around the baby in the womb). Due to little or no amniotic fluid, the baby’s lungs will not develop properly. Bilateral renal agenesis is present in 1 of every 10 000 births. This condition is detected at the fetal anomaly scan. The ultrasound shows limited or absent amniotic fluid, and poorly formed or absent kidneys or lungs. Unfortunately, there is currently no treatment for this condition. Sadly, a baby with Bilateral Renal Agenesis cannot live without kidneys or adequate lung function. For this reason, the baby will not survive until birth, or pass away during birth, or very soon after birth.

  • Lethal Skeletal Dysplasia describes bone abnormalities in the skull, chest or limbs. Severe abnormalities in the chest can limit organ development. Lethal skeletal dysplasia is present in 1 of every 10 000 births. This condition is detected at the fetal anomaly scan. Further scans may be needed to confirm the diagnosis. Unfortunately, there is currently no treatment for this condition. Sadly, due to bone abnormalities limiting organ development, babies do not survive pregnancy or birth.

Tests

  • Ultrasound Scans

    First trimester scan (also known as the nuchal translucency scan)

    An ultrasound is conducted between 11 weeks and 13 weeks 6 days. This involves measuring the thickness of a skin fold at the back of the neck to assess for chromosomal abnormalities.

    Fetal anomaly scan (also known as the morphology scan)

    This ultrasound is used to detect structural abnormalities with your growing baby. It is usually done at 18-20 weeks. If an abnormality is detected, then you will be referred to a specialist.

    Non-invasive Prenatal Testing (NIPT also known as ‘Harmony’)

    NIPT involves a blood test available from 10 weeks which tests for the risk of Down Syndrome, Edwards Syndrome, and Patau Syndrome. It can also identify the sex of the fetus. If a positive test for a chromosomal abnormality occurs, then a referral is made to specialists for further testing. This test detects foetal cells in the maternal blood.

  • Chorionic villus sampling (CVS)

    Chorionic villus sampling is generally conducted from week 13 of pregnancy onwards. A small sample of tissue is taken from the placenta to test.

    This is done in one of two ways:

    Through the abdomen. When the test is conducted this way, an ultrasound guided needle is inserted through the abdomen, into the uterus, and through to the placenta. A sample is then taken of the placenta for testing.

    Through the cervix. When the test is conducted through the cervix, a thin tube with forceps attached is guided through the cervix to the placenta. A sample is then taken of the placenta for testing.

    There are some risks to the test. There is a risk of vaginal bleeding in 10 in every 100 women. There is also a risk of miscarriage in 1 in every 100 women. Similar risk of miscarriage for 2 methods. The baby is monitored via ultrasound for a short time afterwards. There is also a smaller risk of infection due to procedure, and this occurs in 1 in every 1000 women.

    Amniocentesis

    An Amniocentesis is generally conducted from week 16 of pregnancy onwards. A small amount of the fluid inside your uterus is taken to test. An ultrasound guided needle is inserted through abdomen, and into the uterus, where a sample is taken. In less than 7/100 cases, a second attempt may be needed due to there being too small a sample. Similar to the CVS, there is a risk involved with this test, and this risk of miscarriage occurs in 1 in every 200 procedures. To ensure the baby’s safety, the baby is monitored on an ultrasound for a short time afterwards to make sure there are no complications. There is also a risk of infection due to procedure, and this occurs in 1 in every 1000 women.

    Things to watch out for after amniocentesis or CVS:

    • A high temperature (38 degrees or higher)

    • Heavy vaginal bleeding

    • Shivering or feeling like you have the chills

    • Pain that is too much or ongoing

    • Contractions

    • Clear fluid from the vagina

    If you do experience any of the above, it is important to contact the hospital where you had your termination, or your GP.

  • Health Centre for Genetics. (2013). Genetics Fact Sheets. Retrieved from http://www.genetics.edu.au/Publications-and-Resources/Genetics-Fact-Sheets

    NHS Fetal Anomaly Screening Programme. (2017). Fetal anomalies: screening, conditions, diagnosis, treatment. Retrieved from https://www.gov.uk/government/collections/fetal-anomalies-screening-conditions-diagnosis-treatment

    Australian Health Ministers’ Advisory Council 2012, Clinical Practice Guidelines: Antenatal Care – Module 1. Australian Government Department of Health and Ageing, Canberra. http://www.health.gov.au/antenatal

    Mater Mothers. (2017). Ultrasound scan—fetal growth scan. Retrieved from Australian Health Ministers’ Advisory Council 2012, Clinical Practice Guidelines: Antenatal Care – Module 1. Australian Government Department of Health and Ageing, Canberra. http://www.health.gov.au/antenatal

    Mater Mothers. (2015). The Mater Centre for Maternal Fetal Medicine. Retrieved from http://brochures.mater.org.au/brochures/mater-mothers-hospital/the-mater-centre-for-maternal-fetal-medicine

    Queensland Health. (2017). Prenatal screening and testing. Retrieved from https://www.health.qld.gov.au/__data/assets/pdf_file/0022/423931/prenatal-brochure.pdf

    Woolcock, J., & Grivell, R. (2014). Noninvasive prenatal testing. Australian Family Physician, 43(7), 432-4. Retrieved from http://search.informit.com.au.ezproxy.library.uq.edu.au/documentSummary;dn=404550255592646;res=IELHEA