Period 4 weeks and 2 days late but 4 negative home pregnancy tests. what else could be wrong?

Irregular menses: A skipped period frequently means that an ovulation problem occurred during this particular cycle. Menstrual periods occur when Progesterone levels drop without pregnancy 12-14 days after ovulation. Progesterone is not made if ovulation does not occur & frequently that leads to a missed period. Pregnancy is always an option as are other issues.