A great study that exposes the utter absurdity of the ranges currently defined as “normal” for a number of biomarkers, but especially for TSH, prolactin, testosterone, estrogen, liver function, albumin, etc. Out of those, perhaps the most absurd example is the range for TSH. The “normal” range for TSH has been redefined a number of times over the last 30-40 years and each revision pushed the upper limit of normal downwards. Yet, despite this downward trend of the upper limit, the rate of metabolic disease diagnoses keeps increasing. The current upper limit of normal for TSH is 4 despite numerous studies demonstrating poor health in most people with TSH over 2. The study below now adds infertility to the list of problems caused by having TSH smack in the middle of the normal range. Yet, despite their own findings the authors describe the condition as “underactive thyroid within normal range”. LOL, this would have been funny if the issue did not concern the health of millions. How can thyroid be underactive, yet in the normal range!?!? One of these statements must be wrong and since underactive thyroid was an actual finding and it was tied to an actual pathology (female infertility) the only option that remains is that the “normal range” currently used for diagnostic purposes is not at all normal. Hopefully, FDA and Merck (responsible for defining the “normal” ranges for all biomarkers) are taking notice and will finally come up with a range for TSH that truly reflects health/disease.
https://academic.oup.com/jcem/article/103/2/632/4760413
https://www.sciencedaily.com/releases/2017/12/171219144412.htm
“…The study found women who have unexplained infertility were nearly twice as likely to have higher levels of a hormone that stimulates the thyroid gland than women who did not conceive due to known issues with their male partner’s sperm count. Thyroid-stimulating hormone (TSH) is produced by the pituitary gland at the base of the brain and tells the thyroid gland to produce more hormones when needed. Elevated TSH levels can be a sign that the thyroid gland is underactive.”
“…The researchers found that women with unexplained infertility had significantly higher TSH levels than women with infertility due to a known cause. Nearly twice as many women with unexplained infertility had a TSH greater than 2.5 mlU/L compared to women whose partners had male factor infertility. “Since we now know from our study that there is an association between TSH levels at the high end of the normal range and unexplained infertility, it is possible that a high-normal TSH level may negatively impact women who are trying to get pregnant,” Fazeli said. “This could open up new avenues for possible treatments. The next step will be to see if lowering TSH levels will help this group conceive.”
