diff --git a/src/utils_flask_sqla/schema.py b/src/utils_flask_sqla/schema.py
index 2d55091..155a978 100644
--- a/src/utils_flask_sqla/schema.py
+++ b/src/utils_flask_sqla/schema.py
@@ -72,4 +72,5 @@ def __init__(self, *args, **kwargs):
             kwargs["only"] = only
         if exclude:
             kwargs["exclude"] = exclude
+            self.opts.exclude = set(self.opts.exclude) - set(firstlevel_only)
         super().__init__(*args, **kwargs)