diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 79b87df..a4c04f4 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -8847,6 +8847,12 @@
         );
 
     PyType_Ready(&EncodingMapType);
+
+    if (PyType_Ready(&PyFieldNameIter_Type) < 0)
+        Py_FatalError("Can't initialize field name iterator type");
+
+    if (PyType_Ready(&PyFormatterIter_Type) < 0)
+        Py_FatalError("Can't initialize formatter iter type");
 }
 
 /* Finalize the Unicode implementation */