Antenatal diagnosis of Trisomy 21

At Barnet Hospital, Chorionic villus sampling (CVS)/Amniocentesis is offered to pregnant women with a screen positive result on their combined or quadruple screening test. Women are given an appointment at the University College London Hospital (UCLH) Fetal Medicine Unit (FMU).

NIPT (non-invasive prenatal testing) is not offered to women as one of their options for the management of a screen positive result at Barnet/Royal Free hospital Trust (2020). However, the women who are seen at UCLH, are often offered NIPT as part of the care package there.

Questions can be directed to: Fetal Medicine Specialist Midwife, Royal Free London NHS Foundation Trust, Monday – Friday, 8am to 4pm, Telephone: 0208 216 5140, Internal extension: 65140.

The results from diagnostic testing should be communicated directly to the family and to the local fetal medicine specialist midwife by the Fetal Medicine Unit (FMU).

The local midwifery team should offer a face-to-face appointment (within hospital policy access arrangements) to the woman and family to discuss the diagnostic test results with the local fetal medicine specialist midwife.

Test results confirming a diagnosis of Trisomy 21 and subsequent counselling should be given by a trained and experienced professional, in an open, honest and non-judgmental manner. For staff training and guidance in communicating diagnoses of T21 please see:

• “Tell it Right” Training, organised by the DSA. (Appendix 2)

• Feedback from a parent about communicating the diagnosis post-natally (Appendix 11)

Pregnancies should be managed in an obstetric led unit.

The contact details for the local Child Development Team (CDT) should be available to the fetal medicine midwife and obstetric team in the event the family or medical team would like to discuss any specific queries with the CDT in the antenatal period (See Appendix 1 for referral form and contact details). The CDT can also offer opportunities to meet with other families.

Women and families should be given the chance to ask questions and be sign-posted to further resources:

• Antenatal Results and Choices (ARC) website and helpline.

• Down’s Syndrome Association (DSA) website

Written information that can be downloaded e.g. “Looking forward to your baby” leaflet

If anomalies have been diagnosed in pregnancy, families may benefit from the input of relevant specialist paediatric teams for post birth planning.Antenatal diagnosis of Trisomy 21

At Barnet Hospital, Chorionic villus sampling (CVS)/Amniocentesis is offered to pregnant women with a screen positive result on their combined or quadruple screening test. Women are given an appointment at the University College London Hospital (UCLH) Fetal Medicine Unit (FMU).

NIPT (non-invasive prenatal testing) is not offered to women as one of their options for the management of a screen positive result at Barnet/Royal Free hospital Trust (2020). However, the women who are seen at UCLH, are often offered NIPT as part of the care package there.

Questions can be directed to: Fetal Medicine Specialist Midwife, Royal Free London NHS Foundation Trust, Monday – Friday, 8am to 4pm, Telephone: 0208 216 5140, Internal extension: 65140.

The results from diagnostic testing should be communicated directly to the family and to the local fetal medicine specialist midwife by the Fetal Medicine Unit (FMU).

The local midwifery team should offer a face-to-face appointment (within hospital policy access arrangements) to the woman and family to discuss the diagnostic test results with the local fetal medicine specialist midwife.

Management of Pregnancy

Issues relating to the pregnancy:

• There is an increased risk of the following in pregnancies with Down Syndrome:

• Prematurity – the average length of gestation is 38 weeks.

• CTG anomalies in labour – continuous monitoring may be required if identified risks have been ascertained e.g. growth restriction.

• Fetal loss – there is an increased risk of miscarriage, intrauterine fetal death, still birth and neonatal death

Issues relating to the fetus:

• Growth: babies with DS have a lower mean birthweight. Regular growth scans are recommended at 28, 34 and 38 weeks.

• Fetal movements: Fetuses with DS do not have reduced fetal movements, and any pregnancies with reduced fetal movements must be investigated.

• Hydrops: fetal anaemia can be assessed using middle cerebral artery Doppler velocities on ultrasound scan. Hydrops can be idiopathic, secondary to Transient Abnormal Myelopoiesis (TAM) or secondary to cardiac abnormality. Delayed cord clamping should be avoided in labour due to the increased risk of polycythaemia in DS.

• Transient Abnormal Myelopoiesis (TAM) is a pre-leukemic condition affecting up to 10% of neonates with DS and requires prompt referral to a fetal medicine specialist. It can present with hepatosplenomegaly and hydrops.

  Structural anomalies:

  • Congenital Heart Disease (CHD) is present in approximately 40-60% of babies with Down Syndrome. All fetuses should undergo a fetal ECHO.

  • Bowel Atresia may be identified by ultrasound in the third trimester or by the presence of polyhydramnios. If suspected, referral to the neonatal team/paediatric surgeons is required.

  • Brain: mild ventriculomegaly is common and does not require further investigation if identified in isolation.

  • Renal anomalies: Renal pelvis dilatation is more common in Down Syndrome and requires referral to paediatricians/nephrologists.