What is the most likely complication to anticipate in a postpartum mother, aside from postpartum hemorrhage and infection, and what are the risk factors that contribute to it?

Venous Thromboembolism (VTE) is the Most Concerning Postpartum Complication After Hemorrhage and Infection

Venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE), is the most serious and likely complication to anticipate for postpartum mothers after hemorrhage and infection. 1, 2

Epidemiology and Significance

• VTE risk increases throughout pregnancy and peaks during the postpartum period, especially in the first 6 weeks after delivery 2
• VTE is one of the leading causes of maternal mortality in Western nations 3, 4
• The risk remains elevated for up to 6 weeks postpartum, with the highest risk in the first 3 weeks 1

Risk Factors for Postpartum VTE

Major Risk Factors

• Previous history of VTE (unprovoked or estrogen-related) 1
• Known thrombophilia, particularly:
  • Antithrombin deficiency 1
  • Homozygous Factor V Leiden 1
  • Homozygous prothrombin gene mutation 1
  • Compound heterozygosity 1
• Cesarean delivery, especially emergency cesarean section 1, 2
• Postpartum hemorrhage (>1L blood loss) 1, 5
• Postpartum infection 1, 6
• Immobility for ≥1 week antepartum 1
• Peripartum cardiomyopathy 1

Moderate Risk Factors

• Age ≥35 years 1
• BMI ≥30 kg/m² 1
• Multiple pregnancy (twins or higher) 1, 3
• Preeclampsia 1
• Smoking (>10 cigarettes/day) 1, 7
• Family history of VTE in first-degree relative 1
• Protein C or S deficiency 1, 8

Additional Risk Factors

• Blood transfusion during delivery 1
• Preterm delivery 1
• Stillbirth 1
• Systemic lupus erythematosus 1
• Heart disease 1
• Sickle cell disease 1
• Inflammatory bowel disease 1
• Varicose veins 1
• Parity ≥3 1

Clinical Presentation and Diagnosis

• DVT symptoms may include unilateral leg pain, swelling, warmth, and erythema 2, 9
• PE symptoms include dyspnea, chest pain, tachycardia, and hypoxemia 2, 9
• Ovarian vein thrombosis may present with severe abdominal pain, fever, and abdominal distension 3
• Many symptoms of VTE overlap with normal pregnancy changes, making diagnosis challenging 3, 9

Prevention Based on Risk Stratification

• For women with no risk factors: early mobilization and adequate hydration 1
• For women with one major risk factor or ≥2 minor risk factors: thromboprophylaxis with LMWH for at least 10 days after delivery 1
• For women with multiple major risk factors: combined mechanical and pharmacologic prophylaxis, with consideration of extending prophylaxis for 6 weeks 1
• For women with specific thrombophilias and a family history of VTE: prophylaxis with LMWH for 6 weeks postpartum 1

Important Considerations

• The risk of VTE is significantly higher after twin deliveries compared to singleton births 3
• Cesarean delivery increases VTE risk compared to vaginal delivery 1, 2
• Postpartum hemorrhage not only increases VTE risk directly but also often leads to immobility, further increasing risk 1, 5
• The combination of risk factors has a multiplicative effect on overall VTE risk 1

Pitfalls and Caveats

• Signs and symptoms of VTE may be mistaken for normal postpartum changes, leading to delayed diagnosis 3, 9
• The number needed to treat (NNT) to prevent one VTE event varies widely based on risk factors, from 640 in high-risk women to 4000 in lower-risk populations 1
• Pharmacologic prophylaxis carries risks of wound complications and hematomas after cesarean delivery 1
• Underestimation of VTE risk can lead to massive complications, including death 3, 2