This study is prospective, single arm group ,open label, and multicenter trial (with two parallel-group [Hydroxychloroquine 200mg with Aspirin 100mg or Aspirin 100mg])

This study is prospective, open label, and multicenter trial [Hydroxychloroquine 200mg with Aspirin 100mg]

The study population consists of the singleton pregnancy at high risk for preeclampsia who had adverse pregnancy outcome (preeclampsia or fetal growth restriction or intrauterine fetal death) in previous pregnancy.

After randomisation, participants are assigned to receive hydroxychloroquine 200mg with aspirin 100mg per day or aspirin 100mg per day. Treatment is initiated between 12 and 22 weeks' gestation and stopped at 36 weeks' gestation.

The medication adherence to dosing should be maintained at more than 80%.

Inclusion Criteria:

1. The singleton pregnant women aged from 19 to 50 years

2. Includes at least one factors of the below

   ① History of preeclampsia

   ② History of fetal growth restriction

   ③ History of intrauterine fetal death

3. Women who have agreed to enroll in the study and given their informed consent

Exclusion Criteria:

1. Indication to a treatment according to the severe cardiovascular, immune, respiratory, gastrointestinal/liver and biliary system, kidney and urinary system, nervous system, musculoskeletal system, psychiatric, infectious disease and malignancy (However, the participation of the trial is allowed by the investigator based on medically necessary.)

2. Previous inclusion in other intervention study within 3 months of screening (except for non-interventional observational studies)

3. Major malformation of the fetus is diagnosed at 11-13 weeks of gestation

4. Elevated blood concentrations of creatinine more than double the normal value

5. Elevated blood concentrations of liver transaminases (AST(GOT) or ALT(GPT)) more than three times the normal value

6. Conditions related with aspirin treatment

   • Previous exposure within 28 days of screening
   • Previous NSAID exposure within 28 days of screening
   • Bleeding disorder (von Willebrand's disease, peptic ulceration)
   • Hypersensitivity to aspirin

7. Conditions related with hydroxychloroquine treatment

   • Previous exposure within 28 days of screening
   • Hypersensitivity to hydroxychloroquine and 4-aminoquinoline compounds
   • Maculopathy
   • Medications that has potential for visual disturbance
   • Women who have potential for changes in the retina or visual impairment by 4-aminoquinoline compounds
   • Galactose intolerance, Lapp lactase deficiency or glucose-galactose malabsorption
   • Prolonged QT interval on EKG (congenital or acquired) or The risk factors of QT prolongation (heart failure, arrhythmia, myocardial ischemia)
   • Low level of potassium in the blood
   • Low level of magnesium in the blood

8. Not suitable for participant based on medical evidence by investigator