diff --git a/CHANGELOG.md b/CHANGELOG.md
index dcc4f3a..e16cf07 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,8 @@ All notable changes to this project will be documented in this file.
 <a name="unreleased"></a>
 ## [Unreleased]
 
-- Add performance insights retention period
+- fix: retention period for performance insights needs to be null
+- Add 'performance_insights_retention_period' ([#20](https://github.com/umotif-public/terraform-aws-rds-aurora/issues/20))
 
 
 <a name="3.4.0"></a>
diff --git a/README.md b/README.md
index d597a0a..071f4da 100644
--- a/README.md
+++ b/README.md
@@ -177,9 +177,9 @@ No modules.
 | <a name="input_name_prefix"></a> [name\_prefix](#input\_name\_prefix) | Prefix Name used across all resources | `string` | n/a | yes |
 | <a name="input_network_type"></a> [network\_type](#input\_network\_type) | Network type of the cluster. Valid values: IPV4, DUAL. | `string` | `null` | no |
 | <a name="input_parameters"></a> [parameters](#input\_parameters) | A list of parameter objects | <pre>list(object({<br>    name  = string<br>    value = string<br>  }))</pre> | `[]` | no |
-| <a name="input_performance_insights_enabled"></a> [performance\_insights\_enabled](#input\_performance\_insights\_enabled) | Specifies whether Performance Insights is enabled or not. | `bool` | `false` | no |
-| <a name="input_performance_insights_kms_key_id"></a> [performance\_insights\_kms\_key\_id](#input\_performance\_insights\_kms\_key\_id) | The ARN for the KMS key to encrypt Performance Insights data. | `string` | `null` | no |
-| <a name="input_performance_insights_retention_period"></a> [performance\_insights\_retention\_period](#input\_performance\_insights\_retention\_period) | Amount of time in days to retain Performance Insights data. Valid values are 7, 731 (2 years) or a multiple of 31. When specifying performance\_insights\_retention\_period, performance\_insights\_enabled needs to be set to true. | `number` | `7` | no |
+| <a name="input_performance_insights_enabled"></a> [performance\_insights\_enabled](#input\_performance\_insights\_enabled) | specifies whether performance insights is enabled or not. | `bool` | `false` | no |
+| <a name="input_performance_insights_kms_key_id"></a> [performance\_insights\_kms\_key\_id](#input\_performance\_insights\_kms\_key\_id) | the arn for the kms key to encrypt performance insights data. | `string` | `null` | no |
+| <a name="input_performance_insights_retention_period"></a> [performance\_insights\_retention\_period](#input\_performance\_insights\_retention\_period) | amount of time in days to retain performance insights data. valid values are 7, 731 (2 years) or a multiple of 31. when specifying performance\_insights\_retention\_period, performance\_insights\_enabled needs to be set to true. | `number` | `null` | no |
 | <a name="input_permissions_boundary"></a> [permissions\_boundary](#input\_permissions\_boundary) | The ARN of the policy that is used to set the permissions boundary for the role. | `string` | `null` | no |
 | <a name="input_port"></a> [port](#input\_port) | The port on which to accept connections | `string` | `""` | no |
 | <a name="input_predefined_metric_type"></a> [predefined\_metric\_type](#input\_predefined\_metric\_type) | The metric type to scale on. Valid values are RDSReaderAverageCPUUtilization and RDSReaderAverageDatabaseConnections. | `string` | `"RDSReaderAverageCPUUtilization"` | no |
diff --git a/main.tf b/main.tf
index b7ad2d8..4758434 100644
--- a/main.tf
+++ b/main.tf
@@ -330,7 +330,7 @@ resource "aws_rds_cluster_instance" "main" {
   auto_minor_version_upgrade            = var.auto_minor_version_upgrade
   performance_insights_enabled          = var.performance_insights_enabled
   performance_insights_kms_key_id       = var.performance_insights_kms_key_id
-  performance_insights_retention_period = try(var.performance_insights_retention_period, 7)
+  performance_insights_retention_period = var.performance_insights_retention_period
   ca_cert_identifier                    = var.ca_cert_identifier
 
   tags = merge(
diff --git a/variables.tf b/variables.tf
index 822c252..66cfcb3 100644
--- a/variables.tf
+++ b/variables.tf
@@ -242,21 +242,21 @@ variable "tags" {
 }
 
 variable "performance_insights_enabled" {
-  description = "Specifies whether Performance Insights is enabled or not."
+  description = "specifies whether performance insights is enabled or not."
   type        = bool
   default     = false
 }
 
 variable "performance_insights_kms_key_id" {
-  description = "The ARN for the KMS key to encrypt Performance Insights data."
+  description = "the arn for the kms key to encrypt performance insights data."
   type        = string
   default     = null
 }
 
 variable "performance_insights_retention_period" {
-  description = "Amount of time in days to retain Performance Insights data. Valid values are 7, 731 (2 years) or a multiple of 31. When specifying performance_insights_retention_period, performance_insights_enabled needs to be set to true."
+  description = "amount of time in days to retain performance insights data. valid values are 7, 731 (2 years) or a multiple of 31. when specifying performance_insights_retention_period, performance_insights_enabled needs to be set to true."
   type        = number
-  default     = 7
+  default     = null
 }
 
 variable "iam_database_authentication_enabled" {
@@ -468,4 +468,4 @@ variable "network_type" {
   description = "Network type of the cluster. Valid values: IPV4, DUAL."
   type        = string
   default     = null
-}
\ No newline at end of file
+}