You expected to start your monthly bleed a day ago and now you're anxiously waiting. That anxiety will be present whether you wish to be pregnant or not. Of course, certain women whose cycles are always unpredictable grow used to having irregular periods and are a little more blasé when they miss one.

A missed period can indicate you're pregnant
If you are not in menopause, you need to buy a home pregnancy test and use it. The urine pregnancy tests available today are highly sensitive; some can detect very low levels of pregnancy hormone even before a missed period. To be most reliable, though, these tests should be used after you've missed a day or so of bleeding.

Read the instructions on the package carefully. They are less liable to give a misread if they are dipped into a cup of urine rather than held in a free-flowing stream. (If you urinate directly onto the result window, it won't necessarily give a result--and you'll have wasted the $10 test.)

If the urine test is positive:

• start taking a daily multivitamin.
• make a call to an obstetrician and schedule an initial visit.

A missed period can simply be due to irregular cycles
If you're not pregnant, then you will next need to find out when you should be expecting your next period.

• Is your bleeding often irregular? Then track your schedule on a calendar to figure out the usual length of your cycle. A normal cycle can take anywhere from 21 to 40 days, give or take a few days.
• The number of days till you ovulate (when an egg is released from an ovary) varies naturally from woman to woman.
• Once you've ovulated, however, your menstrual bleeding should start in 14 days like clockwork.

Your missed period may be due to a medicine you take, or your lifestyle
If you are not pregnant, but your bleeding is often irregular, know that:

• oral contraceptives can often reduce menstrual bleeding to none.
• some psychiatric medicines can contribute to irregular cycles.
• chemotherapy and hormonally active medicines such as tamoxifen might also be the culprit.
• significant stress can interfere with the menstrual cycle.
• being underweight will also interfere with your period.

You've missed your period because you're entering menopause
By definition, menopause is the cessation of menstrual bleeding; the clinical definition is having had no period for a full year. The beginnings of menopause could be the explanation of your irregular cycles if:

• you are experiencing hot flashes.
• you are in the mid-point of life.

If you are too young to be menopausal and haven't had a period for 3 months, do seek a medical evaluation.