ODP429 Treatment of high-normal TSH levels in women with unexplained infertility is associated with an increased conception rate

• Published in: Journal of the Endocrine Society 2022-11, Vol.6 (Supplement_1), p.A669-A670
• Main Authors: Galbiati, Francesca, Jokar, Tahereh O, Howell, Lars M, Fourman, Lindsay T, Fazeli, Pouneh
• Format: Article
• Language: English
• Subjects: Reproductive Endocrinology
• ISSN: 2472-1972; 2472-1972
• DOI: 10.1210/jendso/bvac150.1385

Unexplained infertility (UI), defined as the inability to conceive after 12 months of unprotected intercourse with no identified cause, affects up to 30% of infertile couples. Women with UI are significantly more likely to have a TSH level in the high-normal range (TSH between 2.5-5 mIU/L) as compared to a control population of women with infertility secondary to a partner with severe oligospermia. It is not known whether treating high-normal TSH levels with levothyroxine results in a higher rate of conception. We performed a cross-sectional study at a large academic health system in women with infertility and TSH levels between 2.5-5 mIU/L to compare rates of conception in women who were treated with levothyroxine versus those who were not treated with levothyroxine. We hypothesized that treatment with levothyroxine would result in a higher conception rate. We identified 126 women who presented for evaluation of infertility between 1/1/2000-6/30/2017 who met our inclusion criteria of a TSH in the high-normal range (2.5 mIU/L < TSH < 5 mIU/L) and either UI (80%, n=101) or infertility due to a severely oligospermic (semen concentration 40% and morphology >4% based on 2010 WHO criteria. Thirty-one percent (n=39) were treated with levothyroxine (LT+) by their primary providers, whereas 69% (n=87) were not treated with levothyroxine (LT-). Women treated with levothyroxine were older than those not treated (mean + SD, LT+: 32.5 + 2.4 years vs LT-: 31. 0 + 3. 0 years, p=0. 005) but were of similar BMI (median (interquartile range), LT+: 24.1 [21.7, 28.3] kg/m2 vs LT-: 23.6 [20.9, 27. 0] kg/m2, p=0.38). Baseline TSH was significantly higher in the group treated with levothyroxine (3.55 [3. 07, 4.19] mIU/L compared to the untreated group (2.93 [2.66, 3.40] mIU/L, p< 0. 0001). In women for whom follow-up data was available (n=105), a significantly higher percentage of women treated with levothyroxine (100%) achieved pregnancy compared to those not treated with levothyroxine (92%, p value 0. 027) and this was also true when only evaluating women with UI (n=86) (LT+: 100% versus LT-: 89.5%,