Thyroid health and fertility are my two favourite topics in my clinics in Whitehorse and Atlin. We know about the critical role of thyroid function in pregnancy health, including miscarriage prevention, which I discuss at length in my online programs. We also know the critical role that Anti-Müllerian Hormone (AMH) plays in evaluating ovarian reserve and egg quality – and therefore fertility.
A recent study in the Journal of Clinical & Diagnostic Research has looked at how thyroid function impacts ovarian reserve – particularly subclinical hypothyroidism where TSH is elevated but thyroid symptoms are not yet present. This is the first study that I have seen that looks specifically at the connection between TSH (thyroid stimulating hormone – a marker of thyroid function for which a higher value denotes that the thyroid is struggling and therefore needs more stimulation) and AMH.
The researchers found that mean TSH was significantly higher (4.74 vs 2.8) in the subgroup with decreased AMH. And inversely, lower healthy TSH levels were found in the subgroup with higher AMH.
There are thyroid receptors on oocytes (eggs in the ovary), which points to an influence of thyroid function on ovarian function. It would thus follow that when doing a fertility work-up, including planning treatment options for a suboptimal AMH level, TSH levels should be evaluated and treated with thyroid hormone replacement, even if it’s in the “normal range” for preconception.
In general with my pre-conception patients I like to see TSH below 2.5 to improve odds of a health TSH in pregnancy as well, and this research confirms this approach of obtaining optimal TSH through the pre-conception period as well.
I hope you have found this helpful, and do let me know if you have any questions!
If you are hungry for more evidence-based information for your fertility or pregnancy journey, visit www.myhealthypregnancyplan.com for free webinars and complete programs.
And if you are a care-provider looking for evidence-based resources for your fertility or pregnancy patients, please get in touch with us at support@myhealthypregnancyplan.com, or visit www.myhealthypregnancyplan.com/ce-courses-for-naturopathic-doctors.
In health,
Dr Jocelyn Land-Murphy, ND
Terra Life
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References:
Singh, S. et al. (2022). Association between Thyroid Function and Ovarian Reserve in Infertile Women: A Cross-sectional Study. Journal of Clinical & Diagnostic Research . Nov2022, 16(11).