Patients with DVT and primary antiphospholipid syndrome have worse obstetric outcomes than pregnant women with DVT and negative antiphospholipid antibodies: a retrospective cohort study.

Background: Pregnant women are at an increased risk of thromboembolism compared with non-pregnant women. Venous thrombosis is a manifestation of antiphospholipid syndrome (APS), an autoimmune thrombophilia associated with pregnancy morbidity.

Objectives: This study was designed to compare gestational outcomes of pregnant patients with deep venous thrombosis (DVT) and primary APS with outcomes of patients with DVT and negative results for antiphospholipid antibodies (aPLs).

Design and setting: This was a retrospective cohort study with data collected from patients with DVT who received prenatal care for autoimmunity and thrombophilia at Hospital Universitário Pedro Ernesto, Rio de Janeiro.

Methods: All patients with DVT were tested for aPLs. Those with positive results were tested again after 12 weeks and classified as having primary APS. Patients with systemic lupus erythematosus, superficial venous thrombosis without DVT, twin pregnancies, or fetuses with congenital malformations were excluded.

Results: This study included 171 patients (39 with APS, 132 with DVT and negative aPL results). Patients with primary APS and DVT had higher frequencies of miscarriages (P = 0.004) and stillbirths during previous pregnancies (P < 0.001). When obstetric outcomes were analyzed prospectively, APS patients had a lower birth weight (P = 0.001) and higher rates of oligohydramnios (P = 0.04), intrauterine growth restriction (P = 0.01), preeclampsia (P = 0.04), stillbirths (P = 0.02), and small-for-gestational-age newborns (P < 0.001) than patients with DVT and negative aPL results. The latter group had gestational outcomes similar to those of the general population.

Conclusions: Patients with primary APS have adverse obstetric outcomes despite appropriate treatment, whereas those with DVT and negative for aPLs have favorable results.