diff --git a/lib/adapters/fetch.js b/lib/adapters/fetch.js
index 1104553..06dece9 100644
--- a/lib/adapters/fetch.js
+++ b/lib/adapters/fetch.js
@@ -155,7 +155,7 @@ export default isFetchSupported && (async (config) => {
     }
 
     if (!utils.isString(withCredentials)) {
-      withCredentials = withCredentials ? 'cors' : 'omit';
+      withCredentials = withCredentials ? 'include' : 'omit';
     }
 
     request = new Request(url, {
@@ -165,7 +165,7 @@ export default isFetchSupported && (async (config) => {
       headers: headers.normalize().toJSON(),
       body: data,
       duplex: "half",
-      withCredentials
+      credentials: withCredentials
     });
 
     let response = await fetch(request);