The purpose of this study is to evaluate the efficacy of potassium iodide during pregnancy on neuro-cognitive development of children followed up until two years.

374 patients with pregnancy less 12 weeks amenorrhea

Patients randomized in 2 parallel groups (each group with 187 patients)

• one group with 200 µg of potassium iodide
• one group with placebo

Follow up during 3 years with :

• a selection visit, an inclusion with randomization before 12 weeks amenorrhea
• and follow up visit at the 5th month and 8th month of pregnancy, the day of birth, and 6, 12, and 24 months " post partum "

Inclusion Criteria:

• Patients with pregnancy less 12 weeks amenorrhea , with clinically normal pregnancy, unique or twiny
• Patients who agree to take part in the study and able to sign an Informed Consent Form

Exclusion Criteria:

• Patients receiving a treatment for thyroid affection, or with thyroid pathology
• Patients with a chronic pathology like insulin dependent diabetes or arterial hypertension
• Patients with a treatment supplying iodine or having had a gynecologic exam with a iodine solution in the last 30 days
• Patients taking part in another clinical test or in the last 30 days
• Patients with depressive antecedent before pregnancy or taking antidepressant treatment
• Psychiatric troubles that may interfere with the clinical evaluation
• Patients under special supervision or trusteeship
• No social security cover