- Subclinical hypothyroidism (SCH) was associated with a lower ovarian reserve during later reproductive age (≥35 years).
- No significant association was observed between thyroperoxidase antibody (TPO-Ab) positivity and ovarian reserve.
Why this matters
- Findings suggest that a thyroid function test should be included in the routine screening protocol for female fertility.
- Findings warrant investigation to determine underlying mechanisms regulating the reduced ovarian reserve and to evaluate whether levothyroxine supplementation may improve the ovarian function of women with SCH.
- Retrospective study included 289 women with SCH and 2279 euthyroid women.
- Ovarian reserve markers such as follicle-stimulating hormone (FSH), the antral follicle count (AFCs) and anti-Müllerian hormone (AMH) levels were compared between euthyroid women and women with SCH.
- Funding: The National Natural Science Foundation of China and others.
- Median AFCs (10 vs 11; P=.013) and AMH (2.05 vs 2.51 ng/mL; P=.015) levels were significantly reduced in women with SCH vs euthyroid women.
- Women with SCH vs euthyroid women had significantly:
- higher FSH (mean difference [MD], 1.13 [95% CI, 0.97-1.29] mIU/mL; P<.001>
- lower AMH level (MD, −0.27 [95%CI, −0.43 to −0.12] ng/mL; P=.001) and AFCs (MD, −0.7 [95% CI, −1.3 to −0.2]; P=.005).
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- Retrospective design.