Women's Health Community

Dear shanbrown: If you happen to be on some kind of hormonal birth control (pill/patch/ring/Mirena) the most likely explanation would be "normal" breakthrough bleeding/spotting due to the hormones in the birth control. One can also have problems with erratic bleeding if one has an infection with chlamydia or gonorrhea. However, if you are not using hormones, and do not have a new sexual partner with chlamydia risks, then the following is my best GUESS.

The most common reason for a menstrual pattern like you have described is not having an ovulation every month. In a normal cycle, estrogen is produced all month. Estrogen is responsible for building up the lining of your uterus so you have something to shed each month.

In a normal cycle, progesterone production increases following ovulation and release of an egg.. Progesterone "stabilizes" the uterine lining in preparation for a possible implantation of a new pregnancy. If you are not pregnant that month the levels of estrogen and progesterone fall, triggering the release of the uterine lining—your period.

So, if you do not ovulate, the estrogen build up of the lining continues, but without the usual ovulation associated progesterone. Thus, the hormone levels don't decline, and the lining stays up inside the uterus—often as a late/ missed period. Alternatively the built up lining can begin to shed erratically yielding flows which are too-light, too- early, or are prolonged.

There can be MANY causes formissing an ovulation(s): low thyroid problems, pituitary problems, ovarian cysts, physical stressors (eg sudden increases in exercise, crash dieting), emotional stressors (problems with boyfriends/girlfriends, money), increased body weight, anorexia, rotating shifts at work, etc. You mentioned abdominal pain/cramping. That MIGHT indicate an ovarian cyst.

Your best bet is to contact your GYN or local county family planning clinic. They can give you the most "for sure" answer, and run some additional tests if necessary.

Yours,
Jane