diff --git a/src/utils.ts b/src/utils.ts
index 3fab96e..8a41976 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -26,7 +26,7 @@ const infoRegexp = /^plantuml(?:@(.+))?:([\w-_.]+)/;
 
 function puFromMd(markdown) {
     const md = new markdownit();
-    const fences = md.parse(markdown)
+    const fences = md.parse(markdown, {})
         .filter(token => token.type === 'fence')
         .filter(token => infoRegexp.test(token.info));