Ben Gocial, M.D.
This is, of course, in light of the negative pregnancy test. If you hadn't done that I'd have recommended that as a first step.
You should see your gynecologist for testing to be sure nothing serious is affecting your cycles.
There are several reasons for the delay in menses. In a reproductive age woman, it is generally related to pregnancy. Typical over the counter pregnancy tests become positive at 2 weeks gestation or one week after implantation. When the pregnancy test is negative, other conditions that can cause a delay in menses include: anovulatory cycle where your body did not release an egg at the appropriate time. Conditions that can be associated with anovulation are emotional stress, weight fluctuation, hormone imbalance such as hyper or hypo thyroidism, or pituitary causes such as a tumor (adenoma) that can increase your body's prolactin level. These can be tested through your blood. You can request for a blood test to check for pregnancy (Bhcg) as well as basic hormone testing through your women's care provider.