$re = '/.*&(.*?)=.*/';
$str = 'http://mytestdomain.com/temp-param-page-2/?wpv_paged_preload_reach=1&wpv_view_count=1&wpv_post_id=720960&wpv_post_search&wpv-women-clothing[]=coats';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php