Thromboembolic disorders—deep venous thrombosis (DVT) or pulmonary embolism (PE)—are a leading cause of maternal mortality.
During pregnancy, risk is increased because:
Venous capacitance and venous pressure in the legs are increased, resulting in stasis.
Pregnancy causes a degree of hypercoagulability.
However, most thromboemboli develop postpartum and result from vascular trauma during delivery (1). The risk of developing a thromboembolic disorder is likely increased for about 6 weeks after delivery. Cesarean delivery, like other surgeries, also increases risk.
Symptoms may be similar to those in nonpregnant patients. Thromboembolic disorders can occur without symptoms, with only minimal symptoms, or with significant symptoms. Also, calf edema, cramping, and tenderness, which may occur normally during pregnancy, may simulate Homans sign (calf discomfort elicited by ankle dorsiflexion with the knee extended).
Septic pelvic thrombophlebitis is a rare postpartum condition in which bacterial infection is present in thrombi that form in the ovarian vein, iliac vein, and/or vena cava. Septic emboli may occur. Septic pelvic thrombophlebitis is suspected in postpartum patients who have fever for at least 3 to 5 days despite antibiotic therapy and with no other identifiable etiology.
Reference
1. American College of Obstetricians and Gynecologists' Committee on Practice Bulletins: Obstetrics. ACOG Practice Bulletin No. 196: Thromboembolism in Pregnancy [published correction appears in Obstet Gynecol. 2018 Oct (reaffirmed 2022);132(4):1068]. Obstet Gynecol. 2018;132(1):e1-e17. doi:10.1097/AOG.0000000000002706
Diagnosis of Thromboembolic Disorders in Pregnancy
For DVT, Doppler ultrasound or sometimes CT with contrast
For PE, helical CT
Diagnosis of DVT is usually by Doppler ultrasound during pregnancy and postpartum. D-dimer levels increase during pregnancy and then decrease gradually postpartum; therefore, this test is not useful during pregnancy or the postpartum period, except if the test is negative (which rules out a thrombus).
If septic pelvic thrombophlebitis is suspected, diagnosis is with CT or MRI.
Diagnosis of PE is increasingly being made by helical CT rather than ventilation-perfusion scanning because CT involves less radiation and is equally sensitive. If the diagnosis of PE is uncertain, pulmonary angiography is required.
Treatment of Thromboembolic Disorders in Pregnancy
≥Safety of Selected Drugs in Pregnancy).
Indications for thrombolysis during pregnancy are the same as for patients who are not pregnant.
If PE recurs despite effective anticoagulation, surgery, usually placement of an inferior vena cava filter just distal to the renal vessels, is indicated.
Key Points
During pregnancy, risk of thromboembolic disorders is increased, but most thromboemboli develop postpartum and result from vascular trauma during delivery.
Symptoms may be similar to nonpregnant patients, but patient may be asymptomatic or symptoms may be mistaken for typical pregnancy symptoms (eg, shortness of breath, low extremity edema).
Diagnose deep vein thrombosis using Doppler ultrasound; if septic pelvic thrombophlebitis is suspected, do CT or MRI.
Diagnose pulmonary embolism using helical CT or, if needed, pulmonary angiography.
Treat high-risk women prophylactically with LMWH as soon as pregnancy is diagnosed and continue until 6 weeks postpartum.
