diff --git a/Include/cpython/abstract.h b/Include/cpython/abstract.h
index 3f834ff727e1d4..7bc80833a746ef 100644
--- a/Include/cpython/abstract.h
+++ b/Include/cpython/abstract.h
@@ -335,12 +335,6 @@ PyAPI_FUNC(void) PyBuffer_Release(Py_buffer *view);
     (Py_TYPE(obj)->tp_iternext != NULL && \
      Py_TYPE(obj)->tp_iternext != &_PyObject_NextNotImplemented)
 
-/* === Number Protocol ================================================== */
-
-#define PyIndex_Check(obj)                              \
-    (Py_TYPE(obj)->tp_as_number != NULL &&            \
-     Py_TYPE(obj)->tp_as_number->nb_index != NULL)
-
 /* === Sequence protocol ================================================ */
 
 /* Assume tp_as_sequence and sq_item exist and that 'i' does not
diff --git a/Misc/NEWS.d/next/C API/2020-04-04-23-51-59.bpo-40170.uXQ701.rst b/Misc/NEWS.d/next/C API/2020-04-04-23-51-59.bpo-40170.uXQ701.rst
new file mode 100644
index 00000000000000..22bdc74904f41c
--- /dev/null
+++ b/Misc/NEWS.d/next/C API/2020-04-04-23-51-59.bpo-40170.uXQ701.rst	
@@ -0,0 +1,3 @@
+Always declare :c:func:`PyIndex_Check` as an opaque function to hide
+implementation details: remove ``PyIndex_Check()`` macro. The macro accessed
+directly the :c:member:`PyTypeObject.tp_as_number` member.
diff --git a/Objects/abstract.c b/Objects/abstract.c
index b5d91dbab0c1df..7e1e51b4c87c2d 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -1309,8 +1309,6 @@ PyNumber_Absolute(PyObject *o)
 }
 
 
-#undef PyIndex_Check
-
 int
 PyIndex_Check(PyObject *obj)
 {