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Women treated for hypothyroidism undergoing IVF experience increased TSH levels
Serum levels of thyroid stimulating hormone increased significantly during in vitro fertilization among women treated for hypothyroidism, according to recent findings.
Researchers evaluated 72 hypothyroid-treated women who underwent in vitro fertilization (IVF) to determine serum TSH modifications. Patients were included if serum TSH was between 0.4-2.5 mIU/L one month before the beginning of the IVF cycle. There were three time point at which serum TSH was tested including: between day 1 and 8 of the cycle before the start of controlled ovarian hyperstimulation, at IVF administration and 16 days following administration.
The researchers found that at the time of administration mean serum levels of TSH were 2.9 ± 1.3 mIU/L rising to 3.2 ± 1.7 mIU/L 16 days following administration. From baseline serum levels of 1.7 ± 0.7 mIU/L there was an 88% increase to 16 days following administration. All comparisons were statistically significant.
The levels of serum TSH were higher than the recommended threshold of 2.5 mIU/L in 46 patients at the time of administration, while 49 patients had TSH levels exceeding the recommended threshold at 16 days post-administration.
“Based on our findings, we suggest strictly monitoring serum TSH in hypothyroid-treated women during IVF cycles and, if necessary, prompt adjustment of the levothyroxine dose,” the researchers wrote. “This is the most pragmatic approach despite the that, to date, it is not supported by clinical evidence. Further studies aimed at clarifying the most suitable therapeutic strategy are warranted.”
Disclosure: The researchers report no relevant financial disclosures.