This site is intended for UK healthcare professionals
Medscape UK Univadis Logo
Medscape UK Univadis Logo
Clinical Summary

Subclinical hypothyroidism tied to lower ovarian reserve in women aged 35 years and older

Takeaway

  • 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.

Study design

  • 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.

Key results

  • 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).
  • In women aged ≥35 years, SCH was associated with significantly higher FSH level (MD, 1.74 [95% CI, 1.49-1.99] mIU/mL) and lower AMH level (MD, −0.40 [95% CI, −0.53 to −0.26] mg/mL) and AFCs (MD, −0.8 [95% CI, −1.5 to −0.2]; P<.001 for all).
  • In women aged <35 years, SCH was linked to higher FSH level (MD, 0.30 [95% CI, 0.23-0.36] mIU/mL; P<.001) and lower AMH level (MD, −0.01 [95% CI,−0.11 to 0.09] ng/mL; P=.84) and AFCs (MD, −0.6 [95% CI, −1.3 to 0.1]; P=.06).
  • SCH was significantly associated with increased FSH and decreased AMH level in women with:
    • tubule factor infertility (P<0.001, and P=0.004), and
    • unexplained infertility (P<0.001, and P=0.041).
  • TPO-Ab positivity was not significantly associated with the FSH, AMH, AFC or the number of aspirated oocytes (P=.42, 0.25, 0.92 and 0.16, respectively).
  • TSH level was significantly positively associated with FSH (P=.025), negatively associated with AMH (p=0.022), AFC (p=0.009) and the number of aspirated oocytes (P=0.038)

Limitations

  • Retrospective design.

References


YOU MAY ALSO LIKE