Presentation: Pregnancy at risk of haemophilia A

A woman attends her booking appointment with her community midwife at her local GP surgery. She is six weeks pregnant with her first baby and is a known carrier of haemophilia A.

• Prenatal testing can be considered when the father is diagnosed with haemophilia A, or when the mother is a carrier or has a family history of haemophilia A.
• Carrier testing should be discussed with women who have a family history of haemophilia A and a pathogenic variant has been identified in the family.

• If seen pre-conceptually, refer the woman to an adult haemostasis consultant based in a haemophilia comprehensive care centre for genomic counselling, consideration of pre-implantation genomic testing and ongoing ‘shared’ pregnancy care with the woman’s local maternity provider.
• Haemostasis consultants with expertise in bleeding conditions will review the NHS England National Genomic Test Directory eligibility criteria, to select which test is relevant for screening.
  • For information about how to arrange testing in Wales, Scotland or Northern Ireland, see our dedicated Knowledge Hub resource.
• Testing options may include:
  • Carrier screening of the patient:
    • R244 Carrier testing for known familial mutation(s): carrier screening for women who have a family history of haemophilia A where a genetic cause has been identified (pathogenic variant). Refer to local protocols, which may involve clinical genetics or haematology teams arranging testing.
  • Prenatal testing in a pregnancy with a known familial disease-causing variant:
    • R251 Non-invasive prenatal sexing (also called non-invasive prenatal testing, or NIPT): for fetal sex determination to inform management in pregnancy. This can be performed after seven weeks of pregnancy, but contact your local Genomic Laboratory Hub (GLH) in advance to determine the local process.
    • Invasive testing for male pregnancies. If NIPD to determine the fetal sex has not been possible, R320 Invasive prenatal diagnosis requiring fetal sexing is available to complete both the fetal sex and haemophilia A testing via the invasive test sample.
  • If the patient presents pre-conceptually, pre-implantation genomic testing for monogenic disorders may be available. Referral via clinical genetics is required.
• For fetal sex NIPD, a blood sample in a Streck tube (or EDTA tube) is required. Please refer to your local GLH for details of test request forms and where to send samples.
• For invasive tests, an amniocentesis or chorionic villus sample, or fetal blood sample (in an EDTA tube) is required, as well as a sample from the mother to test for maternal cell contamination. For many of the tests, parental samples are also needed or are helpful. Please refer to your local GLH for details of test request forms and where to send samples.
• A record of discussion form, or another appropriate local consent form, is required for testing.
• Information about patient eligibility and test indications was correct at the time of writing. When requesting a test, please refer to the National Genomic Test Directory to confirm the right test for your patient.

For clinicians

• Birmingham Women’s and Children’s NHS Foundation Trust: NIPD for prenatal sex determination – R2H1 (PDF, one page)
• NHS England: National Genomic Test Directory
• Royal College of Obstetricians and Gynaecologists: Management of inherited bleeding disorders in pregnancy

For patients

• Haemophilia Society: Understanding haemophilia (PDF, 44 pages)
• NHS: Haemophilia