Incidence, clinical characteristics, and timing of objectively diagnosed venous thromboembolism during pregnancy

• Published in: Primary care update for Ob/Gyns 1998-07, Vol.5 (4), p.155-156
• Main Authors: Gherman, Robert B., Goodwin, T.Murphy, Leung, Belinda, Byrne, James D., Montoro, Martin
• Format: Article
• Language: English
• ISSN: 1068-607X; 1878-4283
• DOI: 10.1016/S1068-607X(98)00044-4

Objective: To determine the incidence, timing, and associated clinical characteristics of objectively diagnosed pregnancy-associated venous thromboembolism (VTE). Methods: A retrospective review of VTE cases occurring between 1978 and 1996 was performed. Cases of deep venous thrombosis (DVT) and pulmonary embolism (PE) were identified by ICD-9 discharge diagnosis code and review of antepartum and coagulation laboratory databases. Study inclusion criteria required the objective diagnosis of VTE with either Doppler ultrasound, impedance plethysmography, pulmonary angiography, ventilation-perfusion scanning, or CT/MRI. Results: Among 268,525 deliveries there were 165 (0.06%) episodes of VTE (1/1627 births). There were 127 cases of DVT and 38 cases of PE. Only 14% (23/165) had a prior history of DVT or PE. Most DVTs occurred in the left leg (104/127, 81.9%). Nearly three quarters of the DVTs (95/127, 74.8%) occurred in the antepartum period. Among the antepartum DVT cases, half were detected prior to 15 weeks of gestation (47/95, 49.5%), with only 28 cases occurring after 20 weeks ( P < .0001). The majority of the PEs occurred in the postpartum period (23/38, 60.5%). There were only 3 maternal deaths due to PE, all associated with cesarean section. Only 1 patient developed PE while on heparin therapy for DVT while 11 others had complications attributable to heparin use. Conclusion: Most pregnancy-related VTE occurs in the antepartum period. The risk of deep venous thrombosis appears to begin early in pregnancy, even before the second trimester. The highest risk period for pulmonary embolism is after cesarean delivery. Maternal complications of heparin anticoagulation during pregnancy are rare.