Today we’re going to chat about your uterus because she is one iodine-hungry organ.

Low uterine and endometrium iodine look different, for different women.

A woman books a fertility workup. Blood tests, thyroid panel, urinary iodine spot test. Everything comes back in range. She is told she is fine but, she’s experiencing recurrent miscarriage.

Another woman has suffered with debilitating periods, mood crashes in the two weeks before her cycle, and breast tenderness so severe she can’t sleep on her front. She’s been told it’s hormonal. She’s been offered an SSRI.

Neither of these women has been tested for what their endometrium is actually doing with iodine because that test doesn’t exist yet, and until very recently, nobody thought to even look there.

Bilal et al. (2020), published in Medical Principles and Practice and co-authored by Dr. David Brownstein, did something rather radical; instead of measuring iodine in blood or urine, they looked directly at iodine transporter activity within endometrial tissue biopsied from women with recurrent pregnancy failures.

Stay with me here as I break this down for you –

They were measuring iodide transporter expression (NIS) and PENDRIN which are proteins that move iodine in and out of cells. This wasn’t a test to see how much iodine was present in these tissues, it was instead looking at how active the movement of iodine was through those tissues.

What they found was that women with two or more recurrent pregnancy failures showed dramatically elevated NIS and PENDRIN expression in their endometrial tissue — more than fivefold — compared to women without a history of pregnancy loss.

A fivefold increase in transporters isn’t pathology. It’s desperation.

Their thyroid markers, urine iodine and thyroglobulin were all unremarkable.

When a tissue such as the endometrium is chronically under-resourced,  it up-regulates and throws open every available door, reaching harder for whatever iodine it can find in circulation, which is exactly what those transporters were doing. Throwing all the doors open, trying desperately to catch a whiff of iodine.

What we need to remember is that the thyroid has evolved priority access to circulating iodine. Whatever we consume via our diet or supplement with, the thyroid takes first. Reproductive tissue and our breast tissue is much further down the queue. When systemic iodine supply is merely marginal, not catastrophically deficient, the uterus loses out first.

And so what are the downstream effects of a shortfall in this one mineral?

• Painful, heavy periods- Iodine has a regulatory effect on the production of inflammatory prostaglandins.
• The classic PMS cluster – PMS symptoms are amplified in an estrogen-dominant tissue environment.
• The luteal phase unravelling – Iodine supports corpus luteum formation which produces progesterone.
• Failure of implantation – Iodine is a signalling molecule for endometrial immune cells.
• Contribution to Endometriosis – Endometriosis is fundamentally an estrogen-dependent condition.

For women who are trying to conceive, the endometrial immune cells that govern implantation eg, natural killer cells, macrophages, stromal cells, also express their very own iodide transporters.

Days 6 to 10 post-ovulation is when the endometrium is at its most receptive for implantation to successfully occur.  When every immune and hormonal signal is converging around the possibility of implantation. If iodine is integral to the endometrial cellular environment, as this research suggests, then this is the window where a tissue deficit in iodine would matter most.

We could make an educated extrapolation that applying InnerKin over the uterus in the lead up to conception, may aid in restoring an endometrial tissue deficit of iodine.

“These findings suggest possible abnormal iodine metabolism and a deficiency of iodine in endometrial tissues from some of the women with reproductive failures.”

I’m not telling you that iodine is the answer to every period problem or every fertility question. This is just one piece of a complex picture but it’s a damn interesting one.

Less than 30% of your body’s iodine is in your thyroid. The thyroid has the highest concentration of iodine per gram of tissue, but because it’s a small gland, it doesn’t hold the majority of the body’s total iodine store. The rest is distributed across a surprisingly long list of tissues, and many of them are reproductive.

Of the tissues that concentrate iodine in the human body, the ovaries have one of the highest concentrations in the body. This single fact is significant and totally underappreciated. The ovaries aren’t a peripheral iodine tissue, they are a primary one. The uterus also concentrates iodine and loses it with age. The implications of deficiency for women hoping to conceive deserve highlighting.

Women using InnerKin over their uterus alongside their breasts have been experiencing a lessening of their typical PMS symptoms, an excellent bonus.

If one is looking to aid preconception health or implantation, you could experiment with using InnerKin in the lead-up to ovulation. For PMS etc you could experiment with applying daily throughout your cycle or daily in the luteal phase only.

Might need to change the name from Breast Tissue Support to All Things Lady Support or something of that nature…..