diff --git a/src/PhpWord/Reader/Word2007.php b/src/PhpWord/Reader/Word2007.php
index deed3ce3..52030ef8 100644
--- a/src/PhpWord/Reader/Word2007.php
+++ b/src/PhpWord/Reader/Word2007.php
@@ -62,6 +62,9 @@ class Word2007 extends AbstractReader implements ReaderInterface
         foreach ($steps as $step) {
             $stepPart = $step['stepPart'];
             $stepItems = $step['stepItems'];
+            if (!isset($relationships[$stepPart])) {
+                continue;
+            }
             foreach ($relationships[$stepPart] as $relItem) {
                 $relType = $relItem['type'];
                 if (isset($stepItems[$relType])) {