Women's Health Community

Dear Rai: The two pregnancy tests were negative, and your flows have arrived on time despite being shorted and lighter. Normally I would say that you are not pregnant, but I would urge you to get a pregnancy test with your GYN or clinic to rule out that your current symptoms are a pregnancy.

If their pregnancy test is negative then the next most common cause of a too light period is not having ovulated that cycle. 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. 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—as either a missed period or a too-light flow where just the top layer is shed.

There can be many causes for not ovulating: thyroid problems, pituitary problems, ovarian cysts, physical stressors (eg sudden increases in exercise, crash dieting), emotional stressors (problems with spouse or boyfriends/girlfriends, money), increased body weight, anorexia, rotating shifts at work, etc. Given your pelvic cramping, you MIGHT have an ovarian cyst.

Bilateral breast tenderness can be a very early sign of pregnancy, appearing as early as two weeks after conception. This is thought to be related to increasing levels of hormones such as estrogen. In a month without an ovulation, not only can a menstrual period be missed, but there can be breast tenderness as well. This is similar to the increased breast tenderness experienced by some women when first taking postmenopausal hormone therapy.

There is a second, less common cause for having a too light period. In some women the estrogen levels become very low. The levels are so low that no uterine lining is available to be shed. This is most common in breastfeeding moms or women with pituitary gland problems.

Lastly, everything I have just shared with you pertains to women who are NOT using a form of hormonal birth control. If you are using a birth control pill/patch/ring/Mirena you may too light periods for an entirely different reason. Once pregnancy has been "ruled out" (because even reliable methods fail) one can usually assume that the too-light period is "normal" or "OK". Unlike the scenarios discussed above, women on hormonal contraception have both estrogen and progesterone available. If the synthetic progesterone is dominant, it can artificially make the uterine lining very thin. So the woman misses her "Pill period" or it is very much lighter than normal. Of note, if you are on a form of hormonal contraception, and you miss a period (s), you will not have a uterine lining build up.

So, I would suggest that you get the final pregnancy test from your GYN. That way, if the test is negative they can asses for an ovarian cyst or other cause of the pregnancy type symptoms.

Yours,
Jane