I am 38 years old and my periods have been 100% regular until this month, when I am now a week late, however myself and my husband always use contraception. I am worries and will do a HPT, however am more concerned that it may be the early menopause, how else would I know and how long should I leave it before I get really worried. I tend to have stress all the time any way and my periods have remained regular throughout, so do not think it is stress related - this is a real suprise to me and I am not sure what to do.