A form of light intermenstrual bleeding consistently timed over a few days to a week before the period starts properly, although it might not happen every month. About 80 percent of the time it signals the presence of endometriosis, making it the most predictive symptom for this condition; about 10 percent of the time it means an abnormality of the uterus such as fibroids, an endometrial polyp or endometritis; the remaining 10 percent of the time there is no explanation found. It has nothing to do with premenstrual tension, which if present is a coincidence.

An inexpensive way of detecting ovulation through the effect progesterone has on the hypothalamus, increasing the body's temperature a few tenths of a degree. Best recorded using a BBT thermometer (with a smaller scale than thermometers used to record fevers or high temperatures) first thing in the morning before rising, and preferably in the vagina for accuracy. Day 1 of the chart is the first morning when there is menstruation (a period). Commonly there's a dip in the temperature just before the sustained rise that indicates that ovulation has occurred (a "biphasic chart"). The chart typically records the days you are menstruating, when you have sex and when you're aware of mucus and ovulation pain. Best used to document: (1) the presence and length of the luteal phase, especially if clomiphene is being used for ovulation induction; and (2) the timing of symptoms such as premenstrual spotting. Not as good for predicting ovulation as LH-testing in urine.

A polyp of the endometrium (lining of the uterus), sometimes without symptoms, sometimes with abnormal bleeding such as intermenstrual bleeding, premenstrual spotting or heavy periods. A cause of infertility (and of failure of assisted conception to result in pregnancy). Diagnosable with transvaginal ultrasound.

A common condition in which tissue like the lining of the uterus (the endometrium), grows somewhere else, sometimes causing dysmenorrhea, premenstrual spotting, infertility, dyspareunia and ovulatory dysfunctional uterine bleeding.

(IMB) Bleeding between periods that are otherwise regular. If it happens while on the oral contraceptive pill it's called breakthrough bleeding; if it happens over a few days before a period starts properly it's premenstrual spotting; if it happens after sex it's postcoital bleeding. These forms of IMB have different, usually important, causes. The formal term for it is metrorrhagia.

A mild pain that precedes ovulation by about 12 hours, felt in the left or right side, but not by everyone or in every ovarian cycle. A good indication of ovulation if it is felt. Can be exaggerated in endometriosis and in so-called pelvic congestion. The time from ovulation pain until the onset of menstruation (ignoring for this purpose any premenstrual spotting) is a good measure of the length of the luteal phase. Should not be treated with NSAIDs such as Advil or Nurofen if you are trying to get pregnant, because these analgesics have been linked to the so-called luteinised unruptured follicle syndrome, or LUF.

Either premenstrual spotting or premenstrual syndrome

A fibroid (or myoma) that grows from the wall of the uterus inwards to distort the endometrial cavity. Can be a cause of menorrhagia (heavy periods), intermenstrual bleeding, premenstrual spotting, infertility and miscarriage.