Levothyroxine supplementation on assisted reproduction technology (ART) outcomes in women with subtle hypothyroidism: a retrospective study

Abstract

The need for treating subclinical hypothyroidism (SCH) in women undergoing assisted reproduction technology (ART) is under debate. Moreover, it is known that controlled ovarian hyperstimulation (COH) protocols may impair the thyroidal axis. Therefore, we evaluated if levothyroxine (L-T4) supplementation in SCH women before undergoing ART positively affects the main reproductive outcomes. We retrospectively analyzed in vitro fertilization (IVF) data of 4147 women submitted to 6545 cycles in a tertiary care IVF Center (January 2009–December 2014). L-T4 (1.4–2.0 mcg/kg) treatment was offered to all women with a pre-cycle TSH >2.5 mIU/L before starting COH and main ART outcomes were compared in euthyroid and L-T4-treated women undergoing ART. Among 4147 women, 1074 (26%) were affected by SCH and were treated with L-T4 before COH was started. No statistically significant differences among L-T4-treated and euthyroid women group were observed regarding pregnancy rate, respectively, per cycle (27.67% vs 26.37%; p = .314) and per embryo transfer (30.13% vs 29.17%; p = .489), live birth rate, respectively, per cycle (21.58% vs 20.38%; p = .304) and per embryo transfer (23.49 vs 22.54%; p = .449) and the rest of primary and secondary efficacy endpoints. Early L-T4 treatment for infertile women with a subtle thyroid dysfunction may mitigate and protect from the negative effects of SCH in the setting of ART, and may preventively overcome also the negative impact of COH on thyroidal axis.

摘要

目前对于接受辅助生殖技术（ART）的妇女治疗亚临床甲状腺功能减退症（SCH）的必要性是有争议的。此外, 已知的控制性超促排卵（COH）方案可能损害甲状腺轴。因此, 我们评估了在接受ART之前, 对SCH女性补充左旋甲状腺素（L-T4）是否会对辅助生殖结局产生积极影响。我们回顾性分析了在一家三级医疗IVF中心（2009年1月至2014年12月）接受了6545个周期的4147名女性的体外受精（IVF）数据。在开始COH之前, 对所有TSH> 2.5 mIU / L的女性提供L-T4（1.4-2.0 mcg / kg）治疗, 比较甲状腺功能正常和接受L-T4治疗的女性的ART结局。在4147名女性中, 有1074名（26％）诊断为SCH, 并在开始COH之前接受L-T4治疗。L-T4治疗组和甲状腺功能正常组女性的妊娠率在每个周期（27.67％vs 26.37％; p = .314）和每次胚胎移植（30.13％vs 29.17％; p =.489）中的差异均无统计学意义。活产率分别为每个周期（21.58％vs 20.38％; p = .304）和每次胚胎移植（23.49 vs 22.54％; p = .449）, 差异无统计学意义。其余的主要和次要疗效终点之间的差异均无统计学意义。对于具有亚临床甲状腺功能减退的不孕妇女, 早期L-T4治疗可以减轻SCH对ART治疗中的负面影响, 并且还可以预防性地减少COH对甲状腺轴的负面影响。

Keywords:

• Female infertility
• subclinical thyroid dysfunction
• levothyroxine treatment
• controlled ovarian hyperstimulation
• assisted reproductive technology

Acknowledgments

The authors wish to acknowledge and sincerely thank all the Humanitas Fertility Center staff for their support in conducting this study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

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Additional information

Funding

This research was partially supported by a grant from the Ibsa Pharmaceuticals, Italy.