diff --git a/lib/helpers/yarn.js b/lib/helpers/yarn.js
index 254ed8ce7d4692e23ac522b8a3b4b02bc49d6bb0..1dfc24f75c3947e071d487d82e1e5e504dbe5d13 100644
--- a/lib/helpers/yarn.js
+++ b/lib/helpers/yarn.js
@@ -89,9 +89,13 @@ async function maintainLockFile(inputConfig) {
     'yarn.lock'
   );
   logger.debug(`Checking for ${yarnLockFileName}`);
-  const existingYarnLock = await inputConfig.api.getFileContent(
-    yarnLockFileName
+  let existingYarnLock = await inputConfig.api.getFileContent(
+    yarnLockFileName,
+    inputConfig.branchName
   );
+  if (!existingYarnLock) {
+    existingYarnLock = await inputConfig.api.getFileContent(yarnLockFileName);
+  }
   logger.silly(`existingYarnLock:\n${existingYarnLock}`);
   if (!existingYarnLock) {
     return null;
diff --git a/test/helpers/yarn.spec.js b/test/helpers/yarn.spec.js
index 8ba85f918caad1b174188ca83418cebe7d8211ef..7fc737a4408796e73262c8208d8d7a29d4f926a8 100644
--- a/test/helpers/yarn.spec.js
+++ b/test/helpers/yarn.spec.js
@@ -69,7 +69,7 @@ describe('maintainLockFile(inputConfig)', () => {
   });
   it('returns null if no file to maintain', async () => {
     const yarnLock = await yarnHelper.maintainLockFile(config);
-    expect(config.api.getFileContent.mock.calls.length).toBe(2);
+    expect(config.api.getFileContent.mock.calls.length).toBe(3);
     expect(yarnLock).toEqual(null);
   });
   it('returns null if contents match', async () => {