We receive a lot of questions in regards to missed periods and negative pregnancy tests. questions like Am I pregnant? Could I be pregnant?

Of course pregnancy is the first thing that we think of when our period is delayed or missed especially if sexual activity has taken place. But there are other reasons for you to have a late or missed period. Pregnancy is not the only reason for people to have a late period.

Here are the 12 most common reasons that you’ve missed your period:

1. Stress
Stress can affect many functions of our bodies including our periods. Scientists know that stress boosts levels of stress hormones – glucocorticoids such as cortisol. Elevated cortisol can inhibit the body’s main sex hormone, gonadotropin releasing hormone (GnRH), and subsequently suppresses ovulation.

Sometimes we can get so stressed out that our body decreases the amount of this Gonadotropin-releasing hormone. This hormone receives instruction from the pituitary gland and is necessary to set in motion activity from other hormones to instruct the ovaries to produce and release and an egg during ovulation and then subsequent menstruation occurs.

Working with your doctor or midwife can help you figure out what you need to do to relax and get back on schedule. This can sometimes take a few months or more to work itself out.

2. Illness
A sudden, short illness or even a longer illness can cause your periods to be delayed. If you get a bad case of the flu or a stomach bug you might skip your period for the month.

Irritable Bowel can also cause you to skip a period here and there. This is usually temporary but talk to your doctor about when to expect your period to return.

3. Change in Schedules
Changing schedules can really throw off the natural rhythms of your body. This is particularly true if you work shift work. Did you also know that many women travelers find their usual menstrual cycle changes or even stops while they’re on the road.

4. Change in Medications
Although it is not always conclusive many medications can affect menstruation. Medications such as antidepressants, blood pressure pills, and even antibiotics can affect your periods. Be sure to talk to your doctor or midwife about any side effects. Missed or irregular cycles can be very common with some methods of birth control. If you change medications, be sure to ask what effects this may have on your period.

5. Being Overweight
Carrying around too much weight can shift or disrupt your cycles or even stop them. Basic cholesterol compounds in fat cells can change into a type of weak estrogen called estrone. Overweight or obese women carrying extra fat cells have little estrone-making factories, which have an estrogen effect on glands.

This added estrogen can cause bleeding or menstrual disorders. A woman may go months without ovulating, for example, but the uterine lining is still accumulating — to the point that it becomes unstable. A woman can then have a period that is like a flood and with prolonged or very heavy bleeding. Most women will see a return to normal cycles and fertility with the loss of some weight, even if they are still considered overweight.

6. Being Underweight
If you do not have enough body fat you will not have regular periods, sometimes can even cause your periods to stop all together. This is called amenorrhea. Underweight women and women with eating disorders, like anorexia nervosa, that result in extreme weight loss may also be unintentionally impacting their menstrual cycles.

Women without much fat on their bodies may have fewer periods or go longer without ovulating. These women may be so underweight that their bodies simply stop making estrogen. Additionally, the lack of fat doesn’t allow cells to convert cholesterol into extra estrogen. Typically a weight gain will help you have your periods return.

7. Miscalculation
The menstrual cycle varies from woman to woman. While we say that the average menstrual cycle is 28 days long, that is not true for everyone. Some women have cycles as short as 21 days or as long as 35 days. Sometimes our period is believed to be late when actually we have simply miscalculated. If you have irregular menstrual cycles, but know when you ovulate, look for your period to start about two weeks after you ovulate.

8. Peri-Menopause
Peri-menopause is the period of time where you are transitioning from your reproductive years to your non-reproductive age. Your periods may be lighter, heavier, more frequent or less frequent – but mostly just not normal. If you do not wish to get pregnant, be sure to continue to use birth control because you are still fertile.

9. Menopause
Menopause is when you have reached the point in your life where you will no longer ovulate or menstruate. Menopause is one of nature’s natural events or it can happen surgically through hysterectomy / oophrectomy which means that your uterus and ovaries have been removed or through a chemical cause such as various forms of chemotherapy.

10. Thyroid
The thyroid is a gland that sits in our neck that helps regulate out bodies functions, such as your period. Women who go to their doctor with a complaint of missed period, discover that the doctor will first and foremost do an examination to see if there are any potential thyroid problems.

It is understandable that the thyroid could have an effect on the menstrual cycle, as it is a hormone producer, and the problem with missed period most often is, it is all based around the imbalance of the hormones needed for the reproductive system.

Tuberculosis and Diabetes can also cause you to skip a period here and there.

11. Excessive Exercise
Excessive exercise can cause period irregularities. You may miss your period completely or you may just have symptoms such as spotting or intermittent bleeding, or even painful menstruation. Not every woman that becomes involved in strenuous sports or excessive exercise, will run into these types of problems but it can be a cause of missed or abnormal bleeding.

This can happen because during long regimes of excessive exercise the body needs more energy. While it is producing this new needed energy it ignores some of the other body functions like the menstrual cycle. This is not a dangerous situation but if continued it may be advisable to reduce the amount of exercise.

If this has become a problem for you speak to your doctor as to whether you should continue with your current exercise program, and also to be sure that this is the root cause of the problem and not something else.

It can take several months of missed periods before the menstrual cycle will return to normal, even after stopping excessive exercise completely.

12. Pregnancy
Finally yes, your missed period might be because you’re pregnant! A simple pregnancy test can usually help you determine if you have missed your period because you are pregnant. Home pregnancy test kits that are on the market today are 97% accurate.

If you are pregnant, you should call to make a prenatal appointment.
If you have taken a pregnancy test and it is negative. Most tests advise you to wait another week and retest. If the second test is negative or if you have a good idea of why your period is missing, then you can and should call the doctor or midwife sooner for a physical exam.

A doctor may also perform a blood work  test and can sometimes prescribe medications to help bring on your period.