You mean you've never had a period before, right? The only way it's possible is about 3 weeks or so before your very first period and on. For most women, they have their first period around the age of 12.
You can not stop a menstrual cycle without removing your ovaries. Some birth control pills allow you to skip periods, but this does not stop the cycle.
The first day of a womans menstrual cycle is also the first day of menstruation.
No, the menstrual cycle is regulated by hormones produced by the ovaries, and without ovaries, there would be no ovulation or menstruation.
YES you can still ovulate without a menstrual cycle. Also you can still get pregnant without a period.
Common reasons for not having a menstrual cycle include menopause, pregnancy and after having a hysterectomy. Extreme weight gain or weight loss can also cause a menstrual cycle to stop. Certain types of birth control can also contribute to a lack of periods.
Reproduction (having a baby)
yes
You begin spotting and/or bleeding from your vagina.
yes if they have started ther period or started their menstrual cycle
yes, its just the bodys way of getting back to normal.
If you were pregnant then you'd no longer have a menstrual cycle, if you don't understand that then you should in no way be having sex or sexually active to risk pregnancy. The menstrual cycle is your body preparing for possible pregnancy, when pregnant the cycle is shut down.
No, having multiple sexual partners has no impact on the menstrual cycle at all.The menstrual cycle is the reproductive cycle, it is controlled by hormonal changes within the reproductive organs and so sex does not change the cycle (unless the person falls pregnant). The menstrual cycle can't tell how many sexual partners a person has, nor would there be any reason for the menstrual cycle to change if a person has multiple sexual partners.