Pregnancy outcome of patients following deep venous thrombosis

Objective. To investigate pregnancy outcome of patients with a history of deep vein thrombosis (DVT).

Methods. A population-based study comparing all pregnancies of patients with and without a history of DVT was conducted. Deliveries occurred during the years 1988–2007 at a tertiary Medical Center. Stratified analyses were performed using multivariable logistic regression models and the Mantel-Haenszel technique.

Results. During the study there were 212,086 deliveries, of which 122 (0.06%) occurred in patients with a history of DVT. Using a multivariate analysis, with backward elimination, the following conditions were significantly associated with DVT: advanced maternal age (OR, 1.1; 95% CI, 1.02–1.1; p = 0.004), chronic hypertension (OR, 2.9; 95% CI, 1.4–6.0; p = 0.005) and previous caesarean delivery (OR, 2.8; 95% CI, 1.9–4.1; p < 0.001). Patients with a history of DVT were more likely to have caesarean deliveries (OR, 2.6; 95% CI, 1.8–3.8; p < 0.001) than non-DVT patients. After controlling for possible confounders, such as maternal age, hypertensive disorders, pregestational diabetes and multiple gestations, by using another multivariate analysis with preterm delivery (<37 weeks' gestation) as the outcome variable, DVT was found to be an independent risk factor for preterm birth (OR, 1.8; 95% CI, 1.1–2.9; p = 0.033). This association remained significant after controlling for labor induction, using the Mantel-Haenszel technique (OR, 1.8; 95% CI, 1.1–3.0; p = 0.011). No significant differences were noted between the groups regarding perinatal outcomes such as low Apgar scores, congenital malformations or perinatal mortality.

Conclusions. A history of DVT is an independent risk factor for spontaneous preterm delivery. Nevertheless, in our population it is not associated with adverse perinatal outcome.