Women with homozygous AT deficiency type II heparin-binding site (HBS) are at high risk of pregnancy loss and pregnancy complications.

Data regarding outcome and therapy of pregnancies in patients with homozygous antithrombin (AT) deficiency are very rare. We conducted a retrospective, descriptive investigation with emphasis on the obstetric history of eight women with homozygous AT deficiency heparin-binding site (HBS), who had at least one pregnancy. The aim of the study was to get a better insight into the outcome and identify suitable management procedures of pregnancy in this rare disease. All patients suffered from homozygous AT deficiency caused by the mutation c.391C>T p.Leu131Phe in the AT gene (SERPINC1). The women reported in total 23 pregnancies; one pregnancy was excluded because of induced abortion. We found that only seven out of the 22 analyzed pregnancies ended with a live infant, all of them were born preterm. Among the 15 negative outcomes, seven were early pregnancy losses and eight were intrauterine fetal deaths. We found no clear association between treatment protocols and outcome. Eight pregnancies were not treated at all; all of them ended with pregnancy loss. We conclude that homozygous AT deficiency HBS, a form of severe thrombophilia, is associated with high risk of pregnancy loss and preterm delivery. Rigorous anticoagulation and/or replacement of AT during pregnancy may improve the outcome.