Late or missed periods can also be the result of more complicated or serious medical conditions. Polycystic ovarian syndrome (an imbalance in female sex hormones such as estrogen and progesterone), thyroid disease, pituitary disease, a pituitary tumor, sexually transmitted diseases, infections, perimenopause and menopause have all been linked to menstrual cycle irregularities.
In rare cases, diseases such as diabetes, liver ailments and irritable bowel syndrome can delay or prevent menstruation. Furthermore, medications, including some birth control methods and antidepressants, can also result in lighter, less frequent or missed periods.
For women who recently stopped using birth control, their bodies may take as long as three months to acclimate and resume normal cycles.
So, in short, if you have questions about why you've missed your period and you've ruled out pregnancy, don't worry unnecessarily. Take the next step and consult your medical professional to determine the underlying cause.
We have lots more information about missed periods on the next page.