diff --git a/iterator/cdc.go b/iterator/cdc.go
index cf8f46c..5ed2bce 100644
--- a/iterator/cdc.go
+++ b/iterator/cdc.go
@@ -74,6 +74,11 @@ func NewCDCIterator(ctx context.Context, tableName string, pKey string, sKey str
 		recordsPollingPeriod:   recordsPollingPeriod,
 	}
 
+	// initialize SequenceNumberMap if it is nil
+	if c.lastPosition.SequenceNumberMap == nil {
+		c.lastPosition.SequenceNumberMap = make(map[string]string)
+	}
+
 	// start listening to changes
 	c.tomb, ctx = tomb.WithContext(ctx)
 	c.tomb.Go(func() error {
diff --git a/iterator/combined_iterator.go b/iterator/combined_iterator.go
index 25671a0..a22c6f4 100644
--- a/iterator/combined_iterator.go
+++ b/iterator/combined_iterator.go
@@ -79,7 +79,7 @@ func NewCombinedIterator(
 			IteratorType:      position.TypeCDC,
 			Time:              now,
 			AfterSnapshot:     true,
-			SequenceNumberMap: map[string]string{},
+			SequenceNumberMap: make(map[string]string),
 		})
 		if err != nil {
 			return nil, fmt.Errorf("could not create the CDC iterator: %w", err)