I have heard in quite a few places now that it is possible to be ovulating regularly but not getting a period, or women think they are ovulating but not getting that monthly bleed.

Women who are experiencing amenorrhea will most likely ovulate before they get their first post-amenorrhea period. (A few get an anovulatory period; bleeding without ovulation beforehand). If one happens to have intercourse around the time of this ovulation, it is absolutely possible to get pregnant, therefore getting pregnant without ever getting a period. And that's where the idea of ovulation without a period arises.

But, monthly ovulation without getting a period is only feasible under very limited circumstances:

  1. On the Mirena IUD. The hormone doses are low enough that they do not affect the reproductive system in general; locally the hormones prevent buildup of the uterine lining and thus many women on the Mirena IUD will ovulate but not get a period. (Note that the manufacturer states the Mirena should only be used in women who have been pregnant.)
  2. A physical abnormality that prevents bleeding, such as Asherman's syndrome or a reproductive system defect that does not allow for discharge of the uterine lining.
  3. As stated above, if pregnancy occurs on the first post-amenorrhea ovulation.

Barring that…. The mechanism does not seem plausible.

In a normal menstrual cycle, the egg-containing follicle starts growing at the beginning of the cycle and the uterine lining is thin. As egg/follicle growth and maturation continues, estradiol is secreted. The estradiol leads to an increase in the thickness of the uterine lining. The lining thickens as the dominant follicle is selected and proceeds to maturation. When the egg/follicle is mature, the increased estradiol leads to a sharp peak in luteinizing hormone (LH) that causes ovulation.

I do not believe that it is possible to have this LH surge without sufficient estradiol (and therefore a thick lining to shed).

And while it may be true in a small minority of cases that the lining does not respond to estradiol and get thicker (this IS the case with the Mirena IUD), in a normal menstrual cycle the lining will thicken. My suspicion is that if a woman's lining did not respond to estradiol by thickening, that would always have been the case and she would never have gotten a period – primary amenorrhea.

After ovulation, progesterone is secreted by the cells that surrounded the now-released egg, maintaining the thickness of the lining and causing other changes that prepare the lining to accept an embryo. If no pregnancy occurs, progesterone drops and the lining is shed.

If progesterone levels are lower than normal, the lining is shed earlier.

What do you think? If you believe you're ovulating but not getting a period, have you confirmed an increase in LH by ovulation predictor kits, or confirmed ovulation through temperature charting?

If you are getting changes in cervical mucus each month that seem to indicate ovulation, but no bleed, it is possible that your body is trying to ovulate but not quite succeeding.  If that's the case… Look into whether you might have hypothalamic amenorrhea (HA). (Asherman's syndrome should also be ruled out.)

Nico