Postpartum hypercoagulability and prophylaxis anticoagulants

Blood Clot. [Source]

There is an increase in thromboembolic complications because of the hypercoagulability that exists postpartum.

Pregnancy itself is a factor of hypercoagulability (pregnancy-induced hypercoagulability) as a physiologically adaptive mechanism to prevent postpartum hemorrhage.
However, when combined with an additional underlying hypercoagulable states, the risk of thrombosis or embolism may become substantial.

Anticoagulants may be necessary during pregnancy to prevent or control the following:

• venous thrombosis, 
• pulmonary embolism, 
• rheumatic mitral valve disease, 
• prosthetic heart valves,
• peripartum cardiomyopathy, 
• primary pulmonary hypertension and 
• Eisenmenger’s syndrome.

DVT. [Source]

Pulmonary Embolism. [Source]

 

Prevention of thrombosis with anticoagulants

Prevention of deep vein thrombosis and other types of venous thrombosis may be required if there are certain predisposing risk factors. One example is based on the point system below, where points are summed together to give the appropriate prophylaxis regimen.

Points	Risk factors
1 point Minor factors	Heterozygous for factor V Leiden mutation Heterozygous for factor II mutation Overweight, in this case defined as a BMI > 28 at early pregnancy Caesarean section DVT heredity in a first-degree relative Age > 40 years Pre-eclampsia Hyperhomocysteinemia
2 points Intermediate risk factors	Protein S or C deficiency Immobilization (after e.g. bone fracture or prolonged bed rest
3 points Intermediate risk factors	Homozygous for factor V Leiden mutation Homozygous for factor II mutation
4 points Severe risk factors	Previous DVT Antiphospholipid syndrome without previous DVT Lupus anticoagulant
Very high risk	Artificial heart valves Antithrombin III deficiency Multiple previous thromboses Antiphospholipid syndrome with previous DVT Previous pulmonary embolism

After adding any risk factors together, a total of 1 point or less indicates that no preventive action is needed.
A total of 2 points indicates that short-term prophylaxis, e.g. with low molecular weight heparin, may be used in temporary risk factors, as well as administering prophylactic treatment 7 days postpartum, starting a couple of hours after birth.
A total of 3 points increases the necessary duration of postpartum prophylaxis to 6 weeks.
A risk score of 4 points or higher means that there should probably be prophylaxis in the antepartum period, as well as at least 6 weeks postpartum. A previous distal DVT motivates a minimum of 12 weeks (3 months) of therapeutic anticoagulation therapy. A previous proximal DVT or pulmonary embolism motivates a minimum of 26 weeks (6.5 months) of therapy. If the therapy duration reaches delivery time, the remaining duration may be given postpartum, possibly extending the minimum of 6 weeks postpartum therapy. In a very high risk, there should be a high-dose antepartum prophylaxis, continued at least 12 weeks postpartum.

Women with antiphospholipid syndrome should have an additional low dose prophylactic treatment of Aspirin.

Further Reading:

1. Venös tromboembolism (VTE) - Guidelines for treatment in C counties. Bengt Wahlström, Emergency department, Uppsala Academic Hospital. January 2008
2. Therapeutic anticoagulation in pregnancy. Norfolk and Norwich University Hospital (NHS Trust). Reference number CA3017. 9th June 2006 [review June 2009]