Study based on data concerning the first pregnancy treated and followed up after the diagnosis of oAPS in the NOH-APS cohort, according to clinical results already published; and on a thematic library collected and preserved at the time of the positive pregnancy test.

ADAMTS 13 will be explored in the available samples defined above: ADAMTS13 antigen (presence of the molecule), ADAMTS13 activity (VWF proteolysis activity of the molecule), global autoantibodies against ADAMTS13 (plasma antibodies recognizing solid phase insolubilized ADAMTS13), these 3 parameters for the description of ADAMTS13 being measured using commercially available diagnostic kits, ELISA type, Technozyme® range, Technoclone, Vienna, Austria.

The clinical endpoint evaluated will be the occurrence (yes/no) of preeclampsia, which is assessed globally, all subtypes combined. Then evaluated according to subtype: late preeclampsia from 34 weeks, early preeclampsia before 34 weeks, eclampsia (convulsions), HELLP syndrome, preeclampsia associated with the birth of a small-for-gestational-age child (defined at percentile 10 of the tables adjusted for gestational age and sex; severe: defined at percentile 3), preeclampsia associated with a retro-placental hematoma, ...

Inclusion Criteria:

• Presence of frozen plasma samples from the positive pregnancy test blood sample.
• Adult patients, included in the NOH-APS cohort, who have successfully initiated a new pregnancy after diagnosis of oAPS.

Exclusion Criteria:

• Absence of frozen plasma sample from the blood sample from the positive pregnancy test.
• Patient who objected to the use of their data.

Patients with an initially pure, non-thrombotic oAPS; included in the NOH-APS cohort; having been followed in Nîmes for their first pregnancy following the diagnosis of oAPS; N=513.