Risk factors for venous thromboembolism (VTE) during pregnancy and the postpartum period

Maternal characteristicsPregnancy characteristicsDelivery characteristics
Risk factoraORRisk factoraORRisk factoraOR
Age >35 years1.3IUGR3.8Pre-term delivery2.42.7
Parity ≥32.4Pre-eclampsia2.9–3.1Prolonged labourNA
BMI ≥25 kg·m−21.8–2.4Multiple gestation1.7–4.2Instrumental deliveryNA
Smoker2.1–3.4Caesarean section1.8–3.6
Varicose veins2.4MROP2.2
Thrombophilia3.2–34.4PPH ≥1000 mL4.1
Prior VTE24.8Infection4.1–6.1
Family history of VTENAImmobility7.7–10.8

Adjusted odds ratio (aOR) values are representative and, for clarity, confidence intervals are not included. BMI: body mass index; IUGR: intrauterine growth restriction; MROP: manual removal of placenta; PPH: postpartum haemorrhage; NA: not available. #: incident rate ratio. Reproduced and modified from [12] with permission.