diff --git a/demo/markdownlint-browser.js b/demo/markdownlint-browser.js
index 72769a85..9e6d365f 100644
--- a/demo/markdownlint-browser.js
+++ b/demo/markdownlint-browser.js
@@ -5202,8 +5202,6 @@ function _arrayWithoutHoles(arr) { if (Array.isArray(arr)) return _arrayLikeToAr
 function _arrayLikeToArray(arr, len) { if (len == null || len > arr.length) len = arr.length; for (var i = 0, arr2 = new Array(len); i < len; i++) arr2[i] = arr[i]; return arr2; }
 var _require = __webpack_require__(/*! ../helpers */ "../helpers/helpers.js"),
   addError = _require.addError;
-var emphasisStartTextRe = /^(\S{1,3})(\s+)\S/;
-var emphasisEndTextRe = /\S(\s+)(\S{1,3})$/;
 module.exports = {
   "names": ["MD037", "no-space-in-emphasis"],
   "description": "Spaces inside emphasis markers",
@@ -5261,44 +5259,43 @@ module.exports = {
       } finally {
         _iterator2.f();
       }
-      var _iterator3 = _createForOfIteratorHelper(emphasisTokensByMarker.values()),
+      var _iterator3 = _createForOfIteratorHelper(emphasisTokensByMarker.entries()),
         _step3;
       try {
         for (_iterator3.s(); !(_step3 = _iterator3.n()).done;) {
-          var _emphasisTokens2 = _step3.value;
+          var entry = _step3.value;
+          var _entry = _slicedToArray(entry, 2),
+            _marker = _entry[0],
+            _emphasisTokens2 = _entry[1];
           for (var i = 0; i + 1 < _emphasisTokens2.length; i += 2) {
             // Process start token of start/end pair
             var startToken = _emphasisTokens2[i];
-            var startText = lines[startToken.startLine - 1].slice(startToken.startColumn - 1);
-            var startMatch = startText.match(emphasisStartTextRe);
+            var startLine = lines[startToken.startLine - 1];
+            var startSlice = startLine.slice(startToken.endColumn - 1);
+            var startMatch = startSlice.match(/^\s+\S/);
             if (startMatch) {
-              var _startMatch = _slicedToArray(startMatch, 3),
-                startContext = _startMatch[0],
-                startMarker = _startMatch[1],
-                startSpaces = _startMatch[2];
-              if (startMarker === startToken.text && startSpaces.length > 0) {
-                addError(onError, startToken.startLine, undefined, startContext, [startToken.startColumn, startContext.length], {
-                  "editColumn": startToken.endColumn,
-                  "deleteCount": startSpaces.length
-                });
-              }
+              var _startMatch = _slicedToArray(startMatch, 1),
+                startSpaceCharacter = _startMatch[0];
+              var startContext = "".concat(_marker).concat(startSpaceCharacter);
+              addError(onError, startToken.startLine, undefined, startContext, [startToken.startColumn, startContext.length], {
+                "editColumn": startToken.endColumn,
+                "deleteCount": startSpaceCharacter.length - 1
+              });
             }
 
             // Process end token of start/end pair
             var endToken = _emphasisTokens2[i + 1];
-            var endText = lines[endToken.startLine - 1].slice(0, endToken.endColumn - 1);
-            var endMatch = endText.match(emphasisEndTextRe);
+            var endLine = lines[endToken.startLine - 1];
+            var endSlice = endLine.slice(0, endToken.startColumn - 1);
+            var endMatch = endSlice.match(/\S\s+$/);
             if (endMatch) {
-              var _endMatch = _slicedToArray(endMatch, 3),
-                endContext = _endMatch[0],
-                endSpace = _endMatch[1],
-                endMarker = _endMatch[2];
-              if (endMarker === endToken.text && endSpace.length > 0) {
-                addError(onError, endToken.startLine, undefined, endContext, [endToken.endColumn - endContext.length, endContext.length], {
-                  "editColumn": endToken.startColumn - endSpace.length,
-                  "deleteCount": endSpace.length
-                });
-              }
+              var _endMatch = _slicedToArray(endMatch, 1),
+                endSpaceCharacter = _endMatch[0];
+              var endContext = "".concat(endSpaceCharacter).concat(_marker);
+              addError(onError, endToken.startLine, undefined, endContext, [endToken.endColumn - endContext.length, endContext.length], {
+                "editColumn": endToken.startColumn - (endSpaceCharacter.length - 1),
+                "deleteCount": endSpaceCharacter.length - 1
+              });
             }
           }
         }
diff --git a/lib/md037.js b/lib/md037.js
index 559f9dc8..9e8ba8d2 100644
--- a/lib/md037.js
+++ b/lib/md037.js
@@ -4,9 +4,6 @@
 
 const { addError } = require("../helpers");
 
-const emphasisStartTextRe = /^(\S{1,3})(\s+)\S/;
-const emphasisEndTextRe = /\S(\s+)(\S{1,3})$/;
-
 module.exports = {
   "names": [ "MD037", "no-space-in-emphasis" ],
   "description": "Spaces inside emphasis markers",
@@ -45,51 +42,51 @@ module.exports = {
       }
 
       // Process bare tokens for each emphasis marker type
-      for (const emphasisTokens of emphasisTokensByMarker.values()) {
+      for (const entry of emphasisTokensByMarker.entries()) {
+        const [ marker, emphasisTokens ] = entry;
         for (let i = 0; i + 1 < emphasisTokens.length; i += 2) {
 
           // Process start token of start/end pair
           const startToken = emphasisTokens[i];
-          const startText =
-            lines[startToken.startLine - 1].slice(startToken.startColumn - 1);
-          const startMatch = startText.match(emphasisStartTextRe);
+          const startLine = lines[startToken.startLine - 1];
+          const startSlice = startLine.slice(startToken.endColumn - 1);
+          const startMatch = startSlice.match(/^\s+\S/);
           if (startMatch) {
-            const [ startContext, startMarker, startSpaces ] = startMatch;
-            if ((startMarker === startToken.text) && (startSpaces.length > 0)) {
-              addError(
-                onError,
-                startToken.startLine,
-                undefined,
-                startContext,
-                [ startToken.startColumn, startContext.length ],
-                {
-                  "editColumn": startToken.endColumn,
-                  "deleteCount": startSpaces.length
-                }
-              );
-            }
+            const [ startSpaceCharacter ] = startMatch;
+            const startContext = `${marker}${startSpaceCharacter}`;
+            addError(
+              onError,
+              startToken.startLine,
+              undefined,
+              startContext,
+              [ startToken.startColumn, startContext.length ],
+              {
+                "editColumn": startToken.endColumn,
+                "deleteCount": startSpaceCharacter.length - 1
+              }
+            );
           }
 
           // Process end token of start/end pair
           const endToken = emphasisTokens[i + 1];
-          const endText =
-            lines[endToken.startLine - 1].slice(0, endToken.endColumn - 1);
-          const endMatch = endText.match(emphasisEndTextRe);
+          const endLine = lines[endToken.startLine - 1];
+          const endSlice = endLine.slice(0, endToken.startColumn - 1);
+          const endMatch = endSlice.match(/\S\s+$/);
           if (endMatch) {
-            const [ endContext, endSpace, endMarker ] = endMatch;
-            if ((endMarker === endToken.text) && (endSpace.length > 0)) {
-              addError(
-                onError,
-                endToken.startLine,
-                undefined,
-                endContext,
-                [ endToken.endColumn - endContext.length, endContext.length ],
-                {
-                  "editColumn": endToken.startColumn - endSpace.length,
-                  "deleteCount": endSpace.length
-                }
-              );
-            }
+            const [ endSpaceCharacter ] = endMatch;
+            const endContext = `${endSpaceCharacter}${marker}`;
+            addError(
+              onError,
+              endToken.startLine,
+              undefined,
+              endContext,
+              [ endToken.endColumn - endContext.length, endContext.length ],
+              {
+                "editColumn":
+                  endToken.startColumn - (endSpaceCharacter.length - 1),
+                "deleteCount": endSpaceCharacter.length - 1
+              }
+            );
           }
         }
       }