diff --git a/public/app/plugins/datasource/cloudwatch/datasource.ts b/public/app/plugins/datasource/cloudwatch/datasource.ts
index c098697fb79..2eeb5b06c80 100644
--- a/public/app/plugins/datasource/cloudwatch/datasource.ts
+++ b/public/app/plugins/datasource/cloudwatch/datasource.ts
@@ -139,7 +139,7 @@ export default class CloudWatchDatasource extends DataSourceApi<CloudWatchQuery,
       }
     }
 
-    return period;
+    return period || '';
   }
 
   buildCloudwatchConsoleUrl(