Table 1 Inclusion and exclusion criteria for pregnant women with hereditary thrombophilia

Inclusion criteria

1. Plasma activity levels of AT, PC, or PS when not pregnant are below the lower limits of the adult reference values (generally about 70% for AT, 55–70% for PC, and 60–70% for PS) without the use of warfarin. Individuals with low PS activity measured only during pregnancy must satisfy at least one of inclusion criteria 3–8. In these cases, PS deficiency can be diagnosed if free protein S antigen levels in the second and third trimesters are less than 30% and less than 24%, respectively

2. Japanese pregnant women who delivered from Jan 1, 2014 to Dec 31, 2018

3. One or more family members exhibiting the same symptoms as the patient

4. Past history of early onset thrombosis (age 40 or below)

5. Repeated recurrence of thrombosis

6. Thromboses in unusual sites

7. New onset of thrombosis during current pregnancy or after delivery

8. Patients with diagnosis confirmed by gene analysis

Inclusion criteria 1 and 2 must always be met regardless of items of 3–8

Exclusion criteria

1. Thrombophilia other than AT, PC, and PS deficiency

2. Antiphospholipid syndrome, systemic lupus erythematosus, platelet abnormalities, vascular disorders, blood flow obstruction, paroxysmal nocturnal hemoglobinuria, malignant tumor and other conditions that tend to cause thrombosis

3. Pregnant women who delivered in 2019 (in cases of pregnant women who were managed in 2018)