Prevalence of low antithrombin levels in preeclamptic women and perinatal outcome

Objective. The aim of this study is to evaluate the prevalence of low antithrombin levels in our population in order to assess an intervention trial feasibility. Methods. This is a retrospective study. A database was created by using queries to find out medical records of patients requiring hospitalization for preeclampsia or gestational hypertension or superimposed preeclampsia to chronic hypertension at Modena University Hospital between June 2015 and July 2019. Results. We screened 11845 deliveries. Overall, 221 (1.9%) cases of preeclampsia were identified. Antithrombin level was available for 201 women, thus included in the analysis. Median antithrombin value was 87% (IQ range: 77-98). The prevalence of low antithrombin levels was 9%. Antithrombin < 80% was found in 21% of the subjects. The remnant showed normal values. Median antithrombin was significantly lower in severe respect with mild preeclampsia (83% ± 14 vs 89% ± 14, p = 0.003). The rate of small for gestational age was significantly higher in low antithrombin levels group (44.4% vs 22.4%, p = 0.042). Considering mean values, antithrombin levels were also significantly lower in case of small for gestational age (84% ± 14 vs 89% ± 14; p = 0.040). Conclusions. In our population, low antithrombin levels (1 in 10 patients) were associated with severity of preeclampsia, namely with small for gestational age babies. Data suggest this subpopulation as a better target for trials assessing the efficacy of antithrombin supplementation.