diff --git a/application/controllers/tools/Medical_checkup_report.php b/application/controllers/tools/Medical_checkup_report.php
index a1f0da7e..6b0192c1 100644
--- a/application/controllers/tools/Medical_checkup_report.php
+++ b/application/controllers/tools/Medical_checkup_report.php
@@ -14,8 +14,21 @@ class MedicalCheckupReportPdf extends FPDF
             return;
         }
 
-        // Draw watermark background per page.
-        $this->Image($this->watermarkPath, 23, 102, 164, 102, 'JPEG');
+        // Keep original image ratio to avoid stretched watermark.
+        $info = @getimagesize($this->watermarkPath);
+        if (!$info || intval($info[0]) <= 0 || intval($info[1]) <= 0) {
+            return;
+        }
+
+        $imgW = intval($info[0]);
+        $imgH = intval($info[1]);
+        $drawW = 136.0;
+        $drawH = ($imgH / $imgW) * $drawW;
+
+        // Position tuned to match lab report reference.
+        $x = ($this->GetPageWidth() - $drawW) / 2;
+        $y = 98.0;
+        $this->Image($this->watermarkPath, $x, $y, $drawW, $drawH, 'JPEG');
     }
 
     public function Footer()