diff --git a/frontend/utils/markdown.js b/frontend/utils/markdown.js
index b0bc85e0b..281c7c756 100644
--- a/frontend/utils/markdown.js
+++ b/frontend/utils/markdown.js
@@ -27,7 +27,7 @@ renderer.heading = (text, level) => {
 
 const convertToMarkdown = (text) => {
   // Add TOC
-  text = toc.insert(text, {
+  text = toc.insert(text || '', {
     slugify: (heading) => {
       // FIXME: E.g. `&` gets messed up
       const headingSlug = _.escape(slug(heading));