Period (or menstruation) is the shedding of the uterine wall at regular intervals, approximately every four weeks. Its lasts from 3 to 7 days. Spotting is irregular vaginal bleeding and not associated with the menstrual bleeding. It can occur during ovulation, pregnancy or can be indicative of a uterine disorder.
edit About Spotting and Regular Menstruation
Periods occur on a regular basis in certain mammalian female species, after the attainment of reproductive age. Regulation of this cycle is affected by emotional stress. Period or the menstruation is part of the menstrual cycle in which bleeding occurs.
Spotting is irregular vaginal bleeding and can be due to any of the following reasons: implantation bleeding during pregnancy, hormone fluctuations, miscarriage, stress, or implantation of IUD (intra-uterine device).
edit Associated problems and abnormalities
The most common problem associated with menstruation is PMS or premenstrual syndrome. This is experienced by many girls and women before the onset of menstruation and includes symptoms such as acne, bloating, cramps, bloating backaches, headache, constipation, irritability, food cravings, and more.
Changes in period can be due to hormonal changes, and result in shorter or longer cycles than usual. Menstrual disorders include oligoovulation (irregular ovulation), anovulation (absence of ovulation), hypomenorrhea (very little flow), metrorrhagia (irregular menstruation), menorrhagia (sudden heavy flows), amenorhea (absence of periods for 3-4 months), and others. Any sudden change in your period is a sign that something is amiss and should be discussed with a doctor.
Vaginal bleeding or spotting is usually not associated with regular menstruation. There are several conditions that may cause spotting which include fibroids, cervical cancer, ovarian cysts and cancer, hypothyroidism, hormone therapy, or even sexual intercourse.
Light spotting is also commonly seen during the first three months of pregnancy. More serious bleeding could be due to molar pregnancy, implantation bleeding, inflamed cervix, vaginal infection, fibroids, etc. very heavy bleeding accompanied by cramping during pregnancy is indicative of a serious problem.
"Period vs Spotting." Diffen.com. Diffen LLC, n.d. Web. 27 Nov 2014. < http://www.diffen.com/difference/Period_vs_Spotting >