This document discusses venous thromboembolism (VTE) in pregnancy. It notes that VTE is more common in pregnant women than non-pregnant women, with an incidence of 85/100,000 pregnancies. Risk factors include blood group A, multiple pregnancy, cesarean delivery, and increased age or BMI. Diagnosis involves ultrasound or CT scans, with D-dimer testing not recommended. Treatment involves low molecular weight heparin until diagnosis is ruled out. Specialist obstetric clinics are available at King's Hospital for conditions like preeclampsia, liver disease, rheumatology and more.

1. Venous Thromboembolism
in pregnancy
Ms. Sadia Bhatti
Consultant in Obstetrics and Maternal medicine
General Practitioners Update Course Feb 2015

2. Incidence
• VTE is up to ten times more common in pregnant
women than in non-pregnant women of the
same age.
• The incidence of VTE 85/100,000 maternities.
Twice as many postpartum as antepartum events.
Blood group A, multiple pregnancy, caesarean
section, cardiac disease, delivery at gestational
age of <36 weeks, a body mass index of ≥25, or
more and maternal age of 35 or over were all
found to increase incidence of venous
thromboembolism.

3. Diagnosis
• Compression duplex ultrasound should be undertaken where there is clinical suspicion of DVT. If
ultrasound is negative and there is a low level of clinical suspicion, anticoagulant treatment can be
discontinued.
• When iliac vein thrombosis is suspected (back pain and swelling of the entire limb), magnetic
resonance venography or conventional contrast venography may be considered.
• Where there is clinical suspicion of acute PTE a chest X-ray should be performed. Compression
duplex Doppler should be performed where this is normal. If both tests are negative with persistent
clinical suspicion of acute PTE, a ventilation–perfusion (V/Q) lung scan or a computed tomography
pulmonary angiogram (CTPA) should be performed.
• Women with suspected PTE should be advised that V/Q scanning carries a slightly increased risk of
childhood cancer compared with CTPA (1/280,000 versus less than 1/1,000,000) but carries a lower
risk of maternal breast cancer (lifetime risk increased by up to 13.6% with CTPA, background risk of
1/200 for study population).
• D-dimer testing should not be performed to diagnose acute VTE in pregnancy

4. Investigations before commencing
anti-coagulant therapy
• Before anticoagulant therapy is commenced, blood should be taken for a full blood count,
coagulation screen, urea and electrolytes and liver function tests.
• Performing a thrombophilia screen prior to therapy is not routinely recommended. When
undertaken, thrombophilia screens should be interpreted by clinicians (usually
haematologists) with specific expertise in the area.

5. Management
• In clinically suspected DVT or PTE, treatment with LMWH should be given until the
diagnosis is excluded by objective testing, unless treatment is strongly
contraindicated.
• LMWH should be given daily in two subcutaneous divided doses with dosage titrated against
the woman’s booking or most recent weight. There should be clear local guidelines for the
dosage of LMWH to be used.
• Routine measurement of peak anti-Xa activity for patients on LMWH for treatment of acute
VTE in pregnancy or postpartum is not recommended except in women at extremes of body
weight (less than 50 kg and 90 kg or more) or with other complicating factors (for example
with renal impairment or recurrent VTE) putting them at high risk.

6. What additional therapies should be employed in the
management of VTE in pregnancy?
• In the initial management of DVT, the leg should be elevated and a
graduated elastic compression stocking applied to reduce oedema.
Mobilisation with graduated elastic compression stockings should be
encouraged.
• Consideration should be given to the use of a temporary inferior vena
caval filter in the perinatal period for women with iliac vein VTE, to reduce
the risk of PTE or in women with proven DVT and who have continuing PTE
despite adequate anticoagulation.

7. Maintenance treatment
• Treatment with therapeutic doses of subcutaneous LMWH should be
employed during the remainder of the pregnancy.
• Pregnant women who develop heparin-induced thrombocytopenia or
have heparin allergy and require continuing anticoagulant therapy should
be managed with the heparinoid, danaparoid sodium or fondaparinux,
under specialist advice.
• Because of their adverse effects on the fetus, oral anticoagulants should
not be used for antenatal VTE treatment.

8. Postnatal anticoagulation
• Therapeutic anticoagulant therapy should be continued for the duration of
the pregnancy and for at least 6 weeks postnatally and until at least 3
months of treatment has been given in total.
• Women should be offered a choice of LMWH or oral anticoagulant for
postnatal therapy after discussion about the need for regular blood tests
for monitoring of warfarin, particularly during the first 10 days of
treatment.
• Women should be advised that neither heparin (unfractionated or LMWH)
nor warfarin is contraindicated in breastfeeding.
• Postpartum warfarin should be avoided until at least the third day and for
longer in women at increased risk of postpartum haemorrhage.
• Graduated elastic compression stockings should be worn on the affected
leg for 2 years after the acute event, if swelling persists, to reduce the risk
of post-thrombotic syndrome.

9. Postnatal clinic review
• Postnatal review for women who develop VTE during pregnancy or the
puerperium should, whenever possible, be at an obstetric medicine clinic
or a joint obstetric haematology clinic.
• All women with asymptomatic heritable or acquired thrombophilia should
be considered for LMWH for at least 7 days following delivery, even if they
were not receiving antenatal thromboprophylaxis. This could be extended
to 6 weeks if there is a family history or other risk factors present.
• Women receiving LMWH antenatally should usually continue prophylactic
doses of LMWH until 6 weeks postpartum but a postnatal risk assessment
should be made. If they are receiving long-term anti- coagulation with
warfarin, this can be started when the risk of haemorrhage is low.
• Both warfarin and LMWH are safe when breastfeeding.

12. Specialist Obstetric Clinics at Kings
CLINIC NAME LEAD CLINICIAN SPECIALIST MW/NURSE
Hypertension Clinic (Obs) Mr. Nick Kametas Katherine Clark
Liver/Obs Clinic Ms. Leonie Penna
Rheumatology/Obs Clinic Ms. Sadia Bhatti
Maternal age clinic (40
years and above age0
Ms. Sadia Bhatti
Renal/Obs Clinic Mr. Nick Kametas
High BMI Obstetric Clinic Ms. Devi Subramanian
Fetal Medicine Prof Nicolaides.Ms. Sarah
Bower
Haematology/Sickle Cell
Clinic Obstetric Clinic
Miss Jemma Johns Chiko Emekekwue
FGM assessment clinic Miss Jemma Johns
Preterm Birth Surveillance
clinic
Ms. Meekai To

13. Specialist Gynae Clinics at Kings
CLINIC NAME LEAD CLINICIAN SPECIALIST
NURSE/MIDWIFE
Early Pregnancy &
Gynaecology Assessment
Unit
Miss Jackie Ross and Miss
Jemma Johns
Ms Seanin Traynor
Paediatric & Adolescent
Gynaecology Clinic
Miss Jemma Johns
Ambulatory Gynaecology
Clinic/Ambulatory
Hyperemesis Service
Mr Anthony Davies Ms Kathy Davies
Recurrent miscarriage
clinic
Miss Jemma Johns
Premature Ovarian Failure
clinic
Mr Haitham Hamoda Andrea Yamoah
Menopause Clinic Mr Haitham Hamoda Andrea Yamoah