From the Guidelines
The postpartum period has the highest risk of thrombosis (blood clot formation) during pregnancy.
Key Factors
- The risk of venous thromboembolism (VTE) is four times higher in pregnant women compared to non-pregnant women of similar age 1.
- The incidence of VTE in the postpartum period is five times higher compared to the antenatal period, with a rate of 511.2 per 100,000 women years 1.
- Hypercoagulability, stasis, and vascular injury are all factors associated with the development of thrombosis, and these changes can be seen from conception and may not revert to normal until beyond 6 weeks postpartum 1.
- The use of low molecular weight heparin (LMWH) is recommended as the preferred thromboprophylactic agent in pregnancy and the postpartum period 1.
Risk Assessment
- A risk stratification system is used to identify women who require antenatal and/or postnatal prophylaxis, with factors such as mode of delivery and postpartum complications taken into account 1.
- Women with a previous personal history of deep vein thrombosis or pulmonary embolism who undergo cesarean delivery should receive both mechanical and pharmacologic prophylaxis 1.
- Women with a personal history of an inherited thrombophilia but no previous thrombosis who undergo cesarean delivery should also receive both mechanical and pharmacologic prophylaxis 1.
From the Research
Risk of Thrombosis During Pregnancy
The risk of thrombosis, also known as venous thromboembolism (VTE), is a significant concern during pregnancy. According to various studies, the risk of VTE increases throughout pregnancy and peaks shortly after delivery 2, 3.
Period with the Highest Risk
- The postpartum period has been identified as the time with the highest risk of VTE, with the incidence proportion of postpartum VTE being highest during the first 3 weeks after delivery 4.
- A study found that 60% of VTE cases occurred during the postpartum period, while 40% occurred during the antenatal period 5.
- The risk of VTE remains elevated throughout the first 12 weeks after delivery, especially for women with obstetric complications such as cesarean delivery, preeclampsia, hemorrhage, and postpartum infection 4.
Key Factors Contributing to the Risk
- Cesarean section is a significant risk factor for VTE, with one study finding it to be the most prevalent risk factor among study participants 5.
- Obesity is also a major risk factor, with approximately 40% of study participants being obese 5.
- Thrombophilia, or a tendency to form blood clots, is another significant risk factor, with more than half of pregnancy-related VTE being associated with thrombophilia 2.