diff --git a/ui/src/app/affiliation/affiliation-update.component.ts b/ui/src/app/affiliation/affiliation-update.component.ts
index e7fe29831..082226c99 100644
--- a/ui/src/app/affiliation/affiliation-update.component.ts
+++ b/ui/src/app/affiliation/affiliation-update.component.ts
@@ -208,10 +208,10 @@ export class AffiliationUpdateComponent implements OnInit {
         roleTitle: assertion.roleTitle,
         url: assertion.url,
         startYear: assertion.startYear,
-        startMonth: parseInt(assertion.startMonth || '0'),
+        startMonth: parseInt(assertion.startMonth || '') || null,
         startDay: assertion.startDay,
         endYear: assertion.endYear,
-        endMonth: parseInt(assertion.endMonth || '0'),
+        endMonth: parseInt(assertion.endMonth || '') || null,
         endDay: assertion.endDay,
         orgName: assertion.orgName,
         orgCountry: assertion.orgCountry,