View source for Venous thromboembolism in pregnancy

== Etiology ==

== Pathophysiology ==

* Compression of left iliac vein by gravid uterus
** Most common site is left leg (80%), proximal veins (71%), iliac/femoral veins (64%)

== Differential Diagnosis ==

== Epidemiology ==

* Most commonly in post-partum period (up to 6 weeks)

== Risk Factors ==

* Age &gt;35 years
* Obesity
* Prior DVT
* Family history
* Sickle cell disease
* Thrombophilia
* In vitro fertility (IVF) treatments
* Preeclampsia
* Hyperemesis gravidarum
* C-section, especially as emergency

== Clinical Manifestations ==

* '''LEFT''' clinical prediction tool has a negative predictive value of 100% if all factors are absent
** Left leg
** Edema ≥2cm calf circmference difference
** First trimester presentation

== Investigations ==

* Doppler ultrasound of the extremities is the best initial test
** Serial ultrasound (three over 6-8 days) has a better negative predictive value
* If ultrasound negative but DVT suspicion is high, need iliac vessel imaging
* If ultrasound negative but PE suspicion is high
** Chest X-ray, followed by perfusion scan (without ventilation scan)
* D-dimer not as useful
** Increase as pregnancy progresses (only 1% normal D-dimer in third trimester)
* Bloodwork
** Only do thrombophilia screen if a significant family history or clot is at an unusual site

=== Approach to Diagnosis ===

[[File:mPMIkJ36e6MsFbzKIuDCovUxU0Byx8T7N3a6DOqoyqbXl9jBMtEjf-8o3JUn0wovoywHjrK8dbiS549_XX5JH9dev_Q-iXG_46ZjrsukPN5mOSHq3wEs-3kP_4IMn8ITGf5UXfr0ty4.png|img]]

== Management ==

* Anticoagulation
** If ''attempting to get pregnant'': warfarin, then switch to LMWH when pregnant
** In ''pregnancy'': UFH or LMWH (not warfarin or DOACs)
*** Daily dosing may be equivalent to twice daily dosing in pregnancy
** While ''breastfeeding'': UFH, LMWH, or warfarin (not DOACs)
** Duration is 3 months including 6 weeks postpartum interval (which is highest risk period)
* Only consider an IVC filter if they have an absolute contraindication to anticoagulation

== Prognosis ==

* High morbidity and mortality
* Represents about 15% of maternal mortality

== Further Reading ==

* [https://www.jogc.com/article/S1701-2163(15)30569-7/pdf SOGC 2014 Guidelines on Venous Thromboembolism and Antithrombotic Therapy in Pregnancy]

[[Category:Thrombosis]]
[[Category:Obstetrical medicine]]