SAMSAS update

17 December 2020

The South Australian Maternal Serum Antenatal Screening (SAMSAS) program continues to improve our maternal serum screening service for our patients. We have made a number of changes, described below:

• Screening window

Blood can be collected for 1st trimester screening, from 9 to 14 weeks (9w0d to 14w0d) inclusive. Second trimester screening begins from 14 weeks and 1 day and ends at 20 weeks and 6 days (14w1d-20w6d). Accurate assignment of gestational age is critically important as the concentrations of the measured analytes change throughout pregnancy and small changes can result in large changes in the final risk assessment.

• Ethnicity

Patient ethnicity contributes to the SAMSAS screening algorithm used to generate the risk assessment. To align with SA Health guidelines, SAMSAS has combined South Asian and Oriental ethnic groups to “Asian”. We have also updated the term Afro-Caribbean to African-Caribbean.

• Biochemical only risk assessment

The SAMSAS program makes every effort to deliver an optimal risk assessment utlising biochemical measurements and nuchal transluency (NT). However, if the laboratory has not received an ultrasound report for NT measurement by 14 weeks gestation, SAMSAS will issue a suboptimal biochemical only risk assessment.

• Omega-3 status test for prematurity risk

The South Australian Health and Medical Research Institute (SAHMRI) will be partnering with SAMSAS to offer omega-3 first trimester screening from 2021 for women with singleton pregnancies. This will identify women who can benefit from omega-3 supplementation to reduce their risk of early birth. Updated National Health and Medical Research Council National Pregnancy Care guidelines will recommend assessing omega-3 status and supplementing pregnant women with low omega-3 intakes. The SAMSAS-SAHMRI collaboration, under an MOU agreement, will evaluate the feasibility and uptake of the omega-3 screening using residual sample from the SAMSAS, with the test listed as an option on a new SAMSAS request form.

If you have any clinical enquiries please contact Dr Janice Fletcher, Genetic Pathologist. For scientific matters, contact Enzo Ranieri, Head of Biochemical Genetics on 08 8161 6739 or enzo.ranieri@sa.gov.au