Not able to convert word document to pdf size(50 MB- 200 MB)

Question

I have used below code:-

Microsoft.Office.Interop.Word.Application msWordDoc = null;

            Microsoft.Office.Interop.Word.Document doc = null;

doc = msWordDoc.Documents.Open(ref originalDocPath, ref oMissing, true,

                                                    ref oMissing, ref oMissing, ref oMissing, ref oMissing,

                                                   ref oMissing, ref oMissing, ref oMissing, ref oMissing,
                                                   ref oMissing,ref oMissing, ref oMissing, ref oMissing,
                                                   ref oMissing);

 doc.SaveAs(ref pdfPath,ref fileFormat, ref oMissing, ref oMissing,

                  ref oMissing, ref oMissing, ref oMissing, ref oMissing,

                  ref oMissing, ref oMissing, ref oMissing, ref oMissing,

                  ref oMissing, ref oMissing, ref oMissing, ref oMissing);


But this code doesn't convert big files.