diff --git a/src/outreach/campaign-store.mjs b/src/outreach/campaign-store.mjs
index b70e839..bab7e58 100644
--- a/src/outreach/campaign-store.mjs
+++ b/src/outreach/campaign-store.mjs
@@ -44,9 +44,18 @@ export function listVariants(db, campaignId) {
 // status: 'rascunho' -> 'rodando' -> 'pausado' <-> 'rodando' -> 'concluido'.
 // pause_reason so fica setado quando o novo status e 'pausado'.
 export function setCampaignStatus(db, campaignId, status, pauseReason = null) {
-  db.prepare(
-    `UPDATE outreach_campaigns SET status = ?, pause_reason = ?, updated_at = datetime('now') WHERE id = ?`
-  ).run(status, status === 'pausado' ? pauseReason : null, campaignId);
+  if (status === 'rodando') {
+    // When transitioning to 'rodando', stamp semana_iniciada_em only on first run (if currently NULL)
+    db.prepare(
+      `UPDATE outreach_campaigns
+       SET status = ?, pause_reason = ?, semana_iniciada_em = COALESCE(semana_iniciada_em, datetime('now')), updated_at = datetime('now')
+       WHERE id = ?`
+    ).run(status, status === 'pausado' ? pauseReason : null, campaignId);
+  } else {
+    db.prepare(
+      `UPDATE outreach_campaigns SET status = ?, pause_reason = ?, updated_at = datetime('now') WHERE id = ?`
+    ).run(status, status === 'pausado' ? pauseReason : null, campaignId);
+  }
   return getCampaign(db, campaignId);
 }
 
diff --git a/tests/campaign-store.test.mjs b/tests/campaign-store.test.mjs
index c160b5f..81637b1 100644
--- a/tests/campaign-store.test.mjs
+++ b/tests/campaign-store.test.mjs
@@ -50,6 +50,35 @@ test('setCampaignStatus pausa e resumeCampaign retoma limpando o motivo', () =>
   db.close();
 });
 
+test('setCampaignStatus rodando stamps semana_iniciada_em on first transition', () => {
+  const db = openDb(':memory:');
+  const campanha = createCampaign(db, campanhaBase());
+  assert.equal(campanha.semana_iniciada_em, null);
+
+  const rodando = setCampaignStatus(db, campanha.id, 'rodando');
+  assert.notEqual(rodando.semana_iniciada_em, null, 'semana_iniciada_em should be set on first rodando transition');
+  db.close();
+});
+
+test('setCampaignStatus rodando does not reset already-set semana_iniciada_em', () => {
+  const db = openDb(':memory:');
+  const campanha = createCampaign(db, campanhaBase());
+
+  // Set to rodando first time, which stamps semana_iniciada_em
+  setCampaignStatus(db, campanha.id, 'rodando');
+
+  // Manually set to a known past value via raw SQL
+  const knownTime = '2026-07-15 10:00:00';
+  db.prepare(`UPDATE outreach_campaigns SET semana_iniciada_em = ? WHERE id = ?`).run(knownTime, campanha.id);
+
+  // Call setCampaignStatus again while already 'rodando'
+  const unchanged = setCampaignStatus(db, campanha.id, 'rodando');
+
+  // Verify semana_iniciada_em was not changed
+  assert.equal(unchanged.semana_iniciada_em, knownTime, 'semana_iniciada_em should not be reset on subsequent rodando calls');
+  db.close();
+});
+
 test('resumeCampaign nao faz nada se a campanha nao estiver pausada', () => {
   const db = openDb(':memory:');
   const campanha = createCampaign(db, campanhaBase());