functions.php

add_filter( 'woocommerce_get_breadcrumb', 'custom_breadcrumb', 10, 2 );
function custom_breadcrumb( $crumbs, $object_class ){

	// Loop through all $crumb
	foreach( $crumbs as $key => $crumb ){
		$taxonomy = 'product_cat'; // The product category taxonomy

		// Check if it is a product category term
		$term_array = term_exists( $crumb[0], $taxonomy );

		// if it is a product category term
		if ( $term_array !== 0 && $term_array !== null ) {		

			// Get the WP_Term instance object
			$term = get_term( $term_array['term_id'], $taxonomy );
		
			// Category id
			if ($term->term_id == 18) {
				$pageId = 44;
				$crumbs[$key][1] = get_permalink($pageId);
			}
		}
	}

	return $crumbs;
}