Which are the causes for missing a menstruation?

Answer 1

It could very well be that you are pregnant. If you have had intercourse in the last three months without a condom or pessary, I would advise you to see a doctor and have a pregnancy test.
It also depends on your age and living style. If you had your first menstruation 3-6 months ago, it could just be your body getting itself prepared for a menstruation every month, and it just isn't very regular yet. If this is the case and you have not had any sexual intercourse, most likely you do not have to worry.
Another possibility is if you have low (very, very low) weight. If you are anorexic or get an enormous amount of exercise, your body will stop menstruating. This is not healthy and in this case as well, you are advised to see a doctor.

Answer 2

Generally, not ovulating is the reason for not having a period. The most common cause of not having a period is pregnancy. If you're not pregnant, and not having your period, you need to see the doctor to figure out why you're not ovulating.

Answer 3

Missed period can be an alarm for pregnancy but missed cycle not always means pregnancy. Your cycle could be missed if you had a stress (sometimes exams, meek love or fight with loved ones), if you are sick (some infection diseases), if you dramatically loose a weight, if you have some hormonal disturbances, etc. Discover more in related link (see below "Missed period - are you pregnant?")

Answer 4

Heavy athletic activity, pregnancy, and disease/disorder come to mind.

Answer 5

pregnancy