Pregnancy and preconception & FH thrombosis

Who to refer:

Pregnant

• URGENT REFERRAL – for any patient already taking warfarin, VKA, DOAC, LMWH or fondaparinux. Please see relevant RefHelp guidance for pregnant women on warfarin or DOACs. Patients on oral anticoagulants must be referred urgently.
• HIGH PRIORITY REFERRAL (as early in pregnancy as possible) any of the following:
• previous personal history of VTE
• patient with known high-risk thrombophilia: antithrombin deficiency, protein C deficiency, protein S deficiency, combined defects, homozygotes for FV Leiden and PT20210A
• patient with any known thrombophilia and significant additional risk factors
• patient with antiphospholipid syndrome.

• LESS URGENT:
• patient with lower risk thrombophilia, no personal history of thrombosis
• patient with first degree relative with proven venous thrombosis below age of 45yrs, unprovoked, or provoked by COCP or pregnancy or minor risk factor or associated with known thrombophilia.

• Patient with personal history of arterial thrombosis:
• refer to consultant obstetrician except rare cases where there is a history of  antiphospholipid syndrome, or other rare blood disorder, who should be referred to haematology.

Planning Pregnancy

All referrals should be routine:

• Any women meeting criteria for very urgent or high priority referral in pregnancy should be referred for pre-pregnancy counselling. For patients on long-term anticoagulation, please seek initial advice from the clinician already managing the patient  for the underlying condition. Pre-pregnancy counselling by a haematologist and obstetrician is also recommended.
• Pre-pregnancy counselling/referral pre-pregnancy should be considered for lower risk patients as above. Decision to refer depends on details of the personal and family history.

Who not to refer:

• Patient with unproven VTE or episode where VTE was excluded.
• Patient with family history of arterial thrombosis including thrombotic / embolic stroke
• Patient with family history of VTE in relative > 45 years of age or with major provoking factor (eg surgery, cancer) or unproven history of VTE.

How to refer:

Preconception: refer via SCI Gateway to Haematology

Pregnancy: Make the referral according to priority categories above by SCI Gateway or letter, copying in locality obstetric consultant.

For pregnant patients on anticoagulation, see relevant RefHelp guidance (warfarin / DOACS) – these patients should be referred urgently.

Primary care investigations

• Clinical history and documentation of results of imaging / diagnosis are most important.
• For most patients, sending a thrombophilia screen from primary care is not helpful.

RCOG Guideline on Prevention of VTE in Pregnancy: gtg-37a.pdf (rcog.org.uk)