All women/ couples planning a pregnancy, or who are already pregnant, should have a comprehensive family history recorded.
Women/ couples who are known of a genetic condition or have a relevant family history should be made aware of the availability of Carrier screening and offered referral to specialist services (ie genetics or obstetrics).
Information on carrier screening for at least the more common genetic conditions that affect children (eg cystic fibrosis <link to chapter> [CF], spinal muscular atrophy [SMA], fragile X syndrome [FXS]) should be offered to low-risk women and couples (ie regardless of family history and ethnicity). Women/couples can be offered larger panels of genes for carrier screening (expanded carrier screening, ECS).
The decision to have screening is a personal choice to be made by the individual/couple.
What do I need to know?
Reproductive carrier screening is used to identify carriers of genetic conditions with an or X-linked inheritance pattern.
Information about carrier screening should be offered to all women or couples during pre-conception and early in the pregnancy (ie first trimester). Identifying carrier couples before pregnancy provides greater reproductive options. For example:
- in-vitro fertilisation (IVF) with
- use of donor gametes
- prenatal diagnostic testing
Traditionally, reproductive carrier screening for inherited recessive conditions was offered on the basis of ethnicity. However, this is known to lead to significant under-identification of carrier couples. Given the multicultural nature of society and people of different ethnic backgrounds having children, ethnicity is poorly predictive of carrier frequency in Australia.
The decision to undertake carrier screening is a personal choice to be made by the individual/ couple. Women/ couples should be informed of the benefits, limitations and cost of screening. Ideally, this information is provided pre-pregnancy.
A number of pathology services offer carrier screening, which can be ordered through general practice. However, carrier screening is not available through the Medicare Benefits Schedule (MBS). From November 2023, there will be an MBS item available for carrier screening, fragile X syndrome, SMA and cystic fibrosis. Depending on the test provider:
- screening may look for a limited number of conditions (eg CF, fragile X syndrome [FXS], spinal muscular atrophy) or screen for an expanded range of conditions (ie >100)
- genetic counselling may or may not be available from the pathology provider.
Note: Carriers of haemoglobinopathies may be initially identified through a routine full blood examination (FBE). Mackenzie’s Mission, a national research project funded by the Federal Government, is in progress but closed for further recruitment.
It aims to identify how reproductive carrier screening for an expanded range of conditions can best be made available to Australian couples who want it.
When should I refer?
Couples identified as high risk of having a child with a genetic condition should be offered referral to specialist services (ie genetics or obstetrics), that is couples where both are carriers of the same autosomal recessive condition and/or where the woman is a carrier of an X-linked condition.
Carrier screening needs to occur in a timely manner to provide women or couples with reproductive options. The testing of biological male partners of pregnant female carriers is of particular importance.
Resources for general practitioners