diff --git a/frappe/model/document.py b/frappe/model/document.py
index 21700acab7..e888e76bee 100644
--- a/frappe/model/document.py
+++ b/frappe/model/document.py
@@ -842,9 +842,13 @@ class Document(BaseDocument):
 
 	def is_child_table_same(self, fieldname):
 		"""Validate child table is same as original table before saving"""
+
+		if self.is_new():
+			return False
+
+		same = True
 		value = self.get(fieldname)
 		original_value = self._doc_before_save.get(fieldname)
-		same = True
 
 		if len(original_value) != len(value):
 			same = False