In women who can’t get pregnant, their egg-supporting cells sometimes don’t respond well to thyroid hormone—and this seems to go along with lower levels of proteins needed for fertility.
Claim Context
In women with infertility, reduced expression of thyroid hormone receptors in granulosa and cervical cells is associated with lower levels of fertility markers such as gremlin-1 and prostaglandin synthase 2, suggesting a link between impaired local thyroid hormone signaling and female reproductive dysfunction.
“A study in granulosa and cervical cells from a small cohort of infertile women showed a significant reduction in markers of fertility, including gremlin-1 and prostaglandin synthase 2. Interestingly, these reductions were associated with an altered profile in the expression of TH receptors...”
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
That enhancing local TH signaling in ovarian cells improves fertility outcomes in women with low TH receptor expression.
A double-blind RCT of 150 infertile women with low granulosa cell THRA expression, randomized to receive intrafollicular T3 injection vs. saline during IVF, measuring oocyte quality, fertilization rate, and live birth rate.
That women with low ovarian TH receptor expression have lower ovarian reserve and reduced IVF success rates over time.
A prospective cohort of 300 women undergoing IVF, measuring TH receptor mRNA in granulosa cells at oocyte retrieval, and following for 2 years to assess AMH decline, cycle cancellation rate, and live birth rate.
That women with unexplained infertility have lower granulosa cell TH receptor expression than fertile controls.
A matched case-control study of 120 women with unexplained infertility and 120 fertile controls, comparing THRA and THRB mRNA levels in granulosa cells obtained during IVF.
That serum TSH levels correlate with granulosa cell TH receptor expression in women undergoing fertility evaluation.
A cross-sectional analysis of 200 women presenting for infertility workup, measuring serum TSH, free T4, and TH receptor mRNA in granulosa cells from follicular fluid.
A synthesis of limited human data and animal models linking TH signaling to ovarian function.
A narrative review summarizing the single human cohort study and rodent ovarian TH data, as presented in this manuscript.