The purpose of the study is to evaluate the ability of placental angiogenesis markers to predict the risk of PE in pregnancy in women with primary APS.

To construct reference intervals of placental angiogenesis markers specific to women affected by primary APS in pregnancy by measuring the levels of sFlt-1and PlGF in serum maternal serum and their sFlt-1/PlGF ratio during the trimesters of gestation (I TM, II TM and III TM).

For this aim the study will involve recruiting two groups of subjects, one will be cases and one will be controls.

Inclusion Criteria:

• Group 1

  1. Pregnant patients between the ages of 18 and 45 years.
  2. Diagnosis of primary APS, according to international classification criteria.

• Group 2

  1. Pregnant patients between the ages of 18 and 45 years.
  2. Patients with at least one previous full-term pregnancy.
  3. No diagnosis of APS, according to international classification criteria.

Exclusion Criteria:

• Group 1

  1. PMA pregnancies.
  2. Known chronic pathology in gestational period such as chronic essential hypertension, neurological pathology
  3. Previous thrombotic event
  4. Chronic renal failure not related to AD
  5. Previous history of oncology

• Group 2

  1. Pregnancy by PMA.
  2. Previous history of polyabortion and/or late pregnancy complications.
  3. Known chronic pathology in gestational period such as chronic essential hypertension, neurological pathology
  4. Previous thrombotic event
  5. Previous history of oncology

At least 60 patients aged 18-45 years will be enrolled between the first and third trimester of gestation, specifically 40 pregnant patients with primary APS (Group 1) and 20 pregnant patients without APS (Group 2) followed at the outpatient clinics of Obstetrics and Pregnancy Pathology of the participating centers. All patients will be asked to sign an informed consent prior to the collection of data and biological material.