Screening

Carrier screening

​In the UK, sickle cell and thalassaemia (SCT) screening is offered to pregnant women, and to their reproductive partner when antenatal screening shows the mother is a genetic carrier.[39] UK guidelines recommend considering preconception testing (or premarital testing, if appropriate) for haemoglobinopathies in women from high-risk ethnic groups.[57] If the woman is found to be a carrier, her partner should be offered screening.[57]

The American College of Obstetricians and Gynecologists recommends universal haemoglobinopathy testing for those planning pregnancy.[40][41]​​ Haemoglobin electrophoresis or molecular genetic testing should be performed when planning pregnancy, or at the initial antenatal visit if there are no previous test results available.[40] If a woman is found to be a carrier, her reproductive partner should be offered screening.[41] Information and counselling should be offered alongside screening.[41][42]

Thorough genetic counselling, including a discussion of reproductive options and the option of intrauterine transfusion, should be offered to all individuals who test positive during screening.[37][39]

Antenatal diagnosis

Pre-implantation genetic testing to prevent a pregnancy with alpha-thalassaemia major is an option for prospective parents considering in vitro fertilisation.[37]

Available tests for patients who are already pregnant include chorionic villus sampling (typically performed at 10-12 weeks' gestation in the US; 11-14 weeks' gestation in the UK) and amniocentesis (typically performed after 15 weeks' gestation).[36]​​[37][39]​ These are invasive tests and carry a risk of fetal loss.

Ultrasound is an important non-invasive means of detecting alpha-thalassaemia major in at-risk pregnancies and may reduce the need for invasive testing.​​[58][59][60]​ It is usually performed relatively late in pregnancy.​

Testing of fetal DNA in maternal circulation is emerging as a non-invasive antenatal test for haemoglobinopathies such as thalassaemia and sickle cell disease.[40][61][62]

Newborn screening

Alpha-thalassaemia is not included in the United States Recommended Uniform Screening Panel for state newborn screening programmes. However, current screening methodologies used to detect sickle cell disease (reported by all states) also detect alpha-thalassaemia.[35]

Asymptomatic patient with microcytosis

Screening can also be performed in an asymptomatic patient with mild anaemia and microcytosis to establish a diagnosis and thus avoid unnecessary and perhaps even harmful iron supplementation.

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