Women's Health | Classical HCU

Pregnancy and classical HCU: planning and support

People with classical homocystinuria (HCU) can plan for pregnancy with specialized care. This page brings together questions, family resources and clinical references for conversations with your metabolic and pregnancy-care teams. Your team will build a plan around your own health and treatment.

First, confirm which type of HCU you have

This page focuses on classical HCU caused by cystathionine beta-synthase (CBS) deficiency. Other homocystinurias, including cobalamin-related remethylation disorders and severe MTHFR deficiency, can have different pregnancy considerations. Ask your metabolic team to confirm the diagnosis and the guidance that applies to you.

• HCU Network America: toolkits and diagnosis resources includes a chart comparing the homocystinurias and a classical HCU guide.
• E-HOD: guidelines and recommendations lists separate clinician guidance for CBS deficiency and remethylation disorders.

Before pregnancy: bring your teams together

Classical HCU can increase the risk of blood clots around pregnancy and after delivery. Ask your metabolic specialist and pregnancy-care team how they will involve a blood-clot specialist, review your HCU treatment and nutrition, and arrange genetic counselling if you want it. If you are already pregnant, contact your team promptly to make a plan. Do not change medicines or supplements without them.

• HCU Network America: Family Planning with Homocystinuria (PDF), written by a genetic counsellor, introduces inheritance and family-planning questions.
• HCU Network Australia: fertility, pregnancy and contraception offers a readable overview of classical HCU.

During pregnancy: monitoring and clot prevention

Your care team can review homocysteine and other relevant results, nutrition, medical formula and medicines as needs change. Clinician guidance discusses anticoagulation for many pregnant people with CBS deficiency, with timing shaped by their history and care plan. Ask who is coordinating these decisions and whom to call if you feel unwell. The linked documents are background for your clinicians, not a treatment schedule to follow yourself.

• European CBS deficiency clinical guideline (PDF), particularly the pregnancy, delivery and postpartum section.
• French G2M Network: specialist pregnancy care certificate (PDF), a clinician-facing example of coordinated planning.

Delivery and the weeks afterward

Ask for a written delivery and postpartum plan shared with the hospital team. Include nutrition and hydration, any anticoagulant plan, when to review HCU treatment after birth, and follow-up while clot risk remains elevated. If you hope to breastfeed, ask how your own nutrition and monitoring will be supported. Your clinicians will decide what is appropriate for you.

• HCU Network Australia: pregnancy information explains why care continues after the birth.
• CBS deficiency clinical guideline (PDF) discusses changing dietary needs and clot prevention in the postpartum period.

Community and lived experience

Personal stories can make questions easier to ask, but another person's treatment may be different from yours.

• Danae Bartke's experience with pregnancy and classical HCU (PDF), shared by HCU Network America.
• HCU Network America: Family Planning collection gathers articles and pregnancy stories.
• HCU Network Australia offers additional patient information and community resources.

Connection and support

Your metabolic clinic should guide personal medical decisions. For help finding CanPKU+ information or a community connection, email admin@canpku.org.