If you are a woman who has a normal, regular menstrual period and are many days late now (say 4 or 5 days late for period), you would probably get a home pregnancy test and wonder how long delayed period is normal. When the test comes out negative, you may be confused as to how this can happen. Actually, this is a common experience for many women and there are many possible explanations for this. Read on to learn why the test is negative even when you ARE pregnant.

Late Period Negative Pregnancy Test--Why?

Case 1: You Are Pregnant

If you have missed your period and are starting to experience a few symptoms of early pregnancy, you may be starting to suspect that you are pregnant. However, if your home pregnancy test indicates a negative result, a few reasons may explain this occurrence:

• The home pregnancy test you bought has a low level of sensitivity. The test kit could probably detect hCG (hormone of pregnancy) only at a certain level and is not sensitive to lower levels. Therefore, if you take the test too early, when your hormone levels are not yet very high, the test may come back negative. This is why some brands require you to do the test a day after you missed your period. So, if you really want to know if you are pregnant as early as possible, use a brand with high sensitivity levels and follow instructions to ensure the accuracy of results. This includes using your urine sample first thing in the morning, when it is most concentrated. Try to learn using the test kit and reading the results after the recommended time. Look for the control line, which you will use to compare your results to make the test valid. Give it time to complete the reaction (about 5-10 minutes) before reading and discarding the kit.
• The urine you used was diluted by a large amount of water you drank before taking the test. If you did not use your first urine in the morning, which is concentrated, you might have a negative pregnancy test result. If you cannot take the test early in the morning, try not to drink a lot of fluids and hold your urine before testing.
• Your hCG level has not reached its peak. Women produce hCG hormone at various rates after the fertilized ovum is implanted. On average, hCG levels increase to 20mIU/ml about seven to 10 days after ovulation, but some women may produce less than this, while others have more.
• In rare cases, anti-hCG antibodies in the kit reagent do not react well with the woman's particular hCG, thus delayed positive results occur. This is not common, but it happens even if some women use the more sensitive or expensive brands.
• In some cases, an ectopic pregnancy may occur. Problems with pregnancy may result in low or decreasing hCG levels, leading to negative results even in the presence of pregnancy symptoms.

If you experience symptoms of pregnancy with a late period and negative pregnancy test, it is advisable to consult your physician for a blood test to determine if you are pregnant and to find out why you got a negative result.

Case 2:  When You Are Not Pregnant

A negative pregnancy test can occur when you have a late period and are not pregnant. Your menstrual cycle is under hormonal control. The ovary usually releases one egg (ovulation) each month, and about two weeks after, the uterine lining sheds, resulting in menstruation. If the egg is fertilized, it is implanted into the uterus and menstruation does not occur. However, if ovulation does not occur regularly, the body does not send signals to the uterus to regulate menstruation. Stress, jet lag, lack of sleep and too much exercise can disrupt your hormonal balance and cause a change in your usual menstrual cycle.

How to Deal with Irregular Menstrual Cycle

Some doctors prescribe birth control pills to regulate hormonal levels that help synchronize the functions of the ovaries and the uterus, resulting in regular menstrual cycles. However, the best way to restore normal mestrual cycles is to eat a healthy diet, exercise and get enough rest to reduce stress. You can also ask your doctor to recommend nutritional supplements that may help promote hormonal balance and regulate your menstrual cycles.

Late Period Negative Pregnancy Test--When to Worry

Women who have period 4 days late or longer, or miss their periods more than three times in a row and get negative results in their pregnancy tests must consult a doctor for a thorough evaluation. A problem with the thyroid gland, for example, may interfere with menstrual cycles. Symptoms of thyroid dysfunction include hair loss, extreme tiredness, and weight gain. Another condition that can cause absence of menstrual periods is when the brain produces high levels of prolactin, a hormone that is usually present in breastfeeding moms. If you miss your periods and have a milky discharge from your breasts or symptoms of thyroid problems, consult your doctor. These problems are usually treated with medications which can also help restore your normal menstrual cycles.

Another possibility you might consider is peri-menopause, which can cause irregularities in your periods. This may be confirmed by taking a blood test for FSH (follicle stimulating hormone) levels, which, if elevated, suggests that no ovulation is taking place. This is characteristic of peri-menopause or premature menopause in younger women.

Late Period Negative Pregnancy Test--What to Do

Experts say that the results of a home pregnancy test are more likely to be wrong when it is negative than when it is positive. The presence of hCG hormone is what makes it turn out to be positive, but a negative result does not necessarily mean you are not pregnant. A woman who conceives but tests too soon may obtain negative results if implantation has not taken place. This is the reason why experts recommend taking a pregnancy test at least one week after missing your period, when it is more reliable to expect hCG to show in the urine.

If you think you have already waited long enough and still get negative results, it probably means you are not pregnant. Find out if this is just a temporary delay in your menstrual cycle due to stress or other factors, or if this is due to a medical problem, which needs further investigation.