Guidelines for health practitioners

These guidelines are to support best practice for health practitioners when advising pregnant people in New Zealand of the availability of antenatal screening for Down syndrome and other conditions.

The guidelines for health practitioners will assist practitioners to discuss screening options in a nationally consistent and safe way, and provide pregnant people and whānau with information to make an informed decision about screening. The guidelines are intended for all practitioners involved in aspects of antenatal screening for Down syndrome and other conditions.

Read the Antenatal screening for Down syndrome and other conditions: Guidelines for health practitioners (PDF, 2.6MB)

These guidelines are currently being reviewed and updated. An updated version will be available online in 2024. The current guidelines should be read in conjunction with the March 2023 and March 2018 updates below.

Updates

March 2023

March 2023

From 1 March 2023, the following changes were implemented:

  • serum analyte levels are no longer reported
  • chance of neural tube defects is no longer reported
  • the risk calculation algorithm was updated to use the ASUM equation for calculation of gestational age. 

More detailed information on these changes can be found here: Antenatal screening updates 1 March 2023 (PDF, 210 KB)

March 2018

March 2018

From 26 March 2018, the nasal bone measurement was removed from the risk calculation algorithm for Down syndrome and other conditions. Nasal bone identification was only ever an optional part of this screening, and was only included in the risk calculation algorithm if reported at the same time as the fetal nuchal translucency and crown rump length ultrasound measurements by radiology.

Nasal bone identification was removed from the risk calculation algorithm for Down syndrome and other conditions based on advice from clinical and technical experts. This decision was supported by the Antenatal Screening for Down Syndrome and Other Conditions Technical Working Group and the radiology sector.

Read Removal of measurement of nasal bone (PDF, 174KB) 

 

First trimester ultrasound reports

Reporting templates for radiologists can be found within the New Zealand Obstetric Ultrasound Guidelines.

Read the New Zealand Obstetric Ultrasound Guidelines

The templates aim to ensure consistency of reporting and assist with providing the information that laboratories require to perform first trimester screening for Down syndrome and other conditions.

Please refer to the New Zealand Obstetric Ultrasound Guidelines for further guidance on fetal ultrasound.

Procedures and practices

Health NZ | Te Whatu Ora recommends all pregnant people are offered antenatal screening for Down syndrome and other conditions in either the first or second trimester of pregnancy.

Prior to referral for antenatal screening the health practitioner should talk to the pregnant person and their family/whānau about their medical and family history. The presence of some conditions in the medical history will indicate referral for genetics and/or obstetric specialist consultation.

The health practitioner referring the person for screening must:

  • provide written and verbal information about screening to the person and their family/whānau, and support them to obtain further information if appropriate
  • discuss antenatal screening for Down syndrome and other conditions as early as possible in the pregnancy, to allow people the opportunity to consider participation in screening, ask questions, and seek further information
  • confirm and document informed consent (which may be verbal) prior to ordering screening
  • agree how results will be communicated to the pregnant person and by whom.

Nuchal translucency scan

As specified in the Primary Maternity Services Notice 2021, the nuchal translucency (NT) scan must only be undertaken by accredited practitioners.

Read the Primary Maternity Services Notice 2021 (DOC, 135KB)

Ordering first trimester combined screening and second trimester maternal serum screening

Laboratory request forms can be downloaded here 

Laboratory request form - Antenatal screening for Down syndrome and other conditions (PDF, 162KB)

 

Or are available from:

LabPLUS
Auckland City Hospital
Phone 0800 LAB PLUS (0800 522 7587)
Email lablink@adhb.govt.nz

or

Canterbury Health Laboratories
Christchurch Hospital
Phone 0800 THE LAB (0800 843 522)
Email labinfo@cdhb.health.nz

 

For NT scans, please complete a separate radiology referral form.

Referral to Genetic Services

The referral pathway has been developed as part of the quality improvements for antenatal screening for Down syndrome and other conditions. When there is an increased chance result the lead maternity carer (LMC) may need to offer further information and advice to assist a pregnant person and their family/whānau to make an informed decision about what to do next and this may include a referral to Genetic Services.

Genetic services can provide information and support for families/whānau with, or with increased chance of, a genetic disorder. Referrals to Genetic Services must come from the GP or LMC in the first instance. Please use the Genetic Services Referral form.

Genetic Services Referral form (pdf, 24 KB)

Genetic Services are physically located in Auckland, Wellington, and Christchurch. Telephone, video or in-person consultations are available.

Recommendations

Health NZ | Te Whatu Ora recommends all pregnant people are offered information about screening for Down syndrome and other conditions, preferably in the first trimester of pregnancy.

The choice to have or not have screening is a personal one and unique to each person and their family/whānau. Each pregnant person must be supported in the decisions they make throughout the screening pathway.

Health NZ funds first trimester combined screening and second trimester maternal serum screening for all eligible people (note there may be a surcharge for the ultrasound scan).

Non-invasive prenatal screening

Non-invasive prenatal screening (NIPS) is a way of determining the chance of the baby having certain chromosomal abnormalities such as Down syndrome, Edwards syndrome and Patau syndrome as well as other conditions. It involves a maternal blood test, and it can be performed reliably from 10 weeks of pregnancy. NIPS has the highest sensitivity and specificity of all the screening tests for Down syndrome.

As a primary screening test, NIPS is currently a user pays, non-scheduled test.

NIPS is considered a screening test and does not replace current diagnostic testing using amniocentesis or chorionic villus sampling. Specialist referral is recommended when there is:

  • known fetal abnormality
  • a significantly raised nuchal translucency (NT)
  • an increased chance result from first trimester combined screening or second trimester maternal serum screening.

In these situations, NIPS may be offered by specialist services following initial consultation with the pregnant person, however a private NIPS without specialist input is not appropriate. Lead maternity carers should check with their local specialist service (ie, Maternal Fetal Medicine) to determine whether funded NIPS is offered to people who receive an increased chance screening result.

 

Further information

The NSU Position Statement on NIPS 2019 (available on this page).

NIPS information in Appendix 5 of the New Zealand Obstetric Ultrasound Guidelines (DOC, 9.4MB)

The NZMFMN Statement on the use of Non-Invasive Prenatal Screening (NIPT) (NZMFMN 2016( (PDF, 259KB)

RANZCOG statement: Prenatal screening and diagnostic testing for fetal chromosomal and genetic conditions

 

Downloads

Antenatal screening for Down syndrome and other conditions - Laboratory request form

Antenatal screening for Down syndrome and other conditions - Laboratory request form
This form must be used for requesting first trimester screening [MSS1] between 9w-13w6d (blood test best 9w-10w) and second trimester screening [MSS2] between 14w-20w (best 14w-18w). The form can be completed and signed electronically online. All fields must be completed including current maternal weight and IVF information, to ensure high quality screening results. CRL will be provided to the laboratory by the radiologist after the NT scan, or referrers may provide a CRL measurement from an earlier dating scan if available. The form should be printed and provided to the pregnant person.

NSU statement on Non Invasive Prenatal Screening (NIPS)

NSU statement on Non Invasive Prenatal Screening (NIPS)

Monitoring Reports

Antenatal screening for Down syndrome and other conditions is monitored by Health NZ | Te Whatu Ora, using information from health district laboratory information systems. 

These reports are summary information only and do not contain identifiable data or information.

Downloads

Downloads