ovulation and ovulation prediction tests

Posted By karen on July 26, 1998 at 22:57:40:







I am 34 years old and my husband and I are trying to get pregnant.  I have been using an ovulation prediction test for six days now and am on the 16th day of my cycle (which is 28 days in length) with no positive results yet.  I have read that most women ovulate around the 14th day of their cycle.  Is it common to ovulate at any time during the cycle (other then during menstruation)?  Will I ovulate at about the same time every month or does it change from month to month?  For example, could I ovulate on the 14th day one month and on the 19th day the next?  How accurate are these ovulation testers?  Is it possible to ovulate and have the test show negative?  I have been experiencing "crampiness" for the past couple of days, is this an indication of ovulation?  
Thank you