Research question

To date, most studies have investigated the minimum number of spermatozoa available for intrauterine insemination (IUI), with no data on the maximum number of motile spermatozoa inseminated (NMSI) having been published. This study aimed to determine whether an upper cut-off for the NMSI during IUI exists above which the live birth rate (LBR) is negatively affected.

Design

Retrospective analysis of autologous IUI cycles performed between January 2010 and July 2018 in women <43 years old with a NMSI >1 million. The main outcome was the LBR per IUI cycle as a function of the NMSI.

Results

A total of 2592 IUI cycles performed in 1017 couples were included. The LBR increased with NMSI up to 30 million without any upper threshold (AUC = 0.5441). The LBR per IUI cycle were 14.5%, 17.9% and 22.7% for NMSI of >1 to ≤10, >10 to ≤20 and >20 to ≤30 million, respectively (P = 0.003). By univariate analysis, the NMSI, female age, number of mature follicles and oestradiol concentrations on day of ovulation triggering, cycle number and infertility aetiology influenced the LBR. Multivariate analysis showed that the LBR was 1.49 and 1.78 times higher when IUI was performed with a NMSI >10 to ≤20 million (odds ratio [OR] 1.49; 95% confidence interval [CI] 1.10–2.02]) and >20 to ≤30 million (OR 1.78; 95% CI 1.08–2.94), respectively, compared with IUI with a NMSI >1 to ≤10 million.

Conclusions

The LBR after IUI can be optimized by inseminating a maximum of motile spermatozoa up to 30 million. Thus, in this specific cohort, IUI preparations should not be diluted when more than 10 million motile spermatozoa are obtained.

中文翻译：

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宫内授精后的活产：受精的活动精子数量是否有上限？

 研究问题

迄今为止，大多数研究都调查了可用于宫内授精 (IUI) 的最小精子数量，但尚未发表有关最大活动精子授精数量 (NMSI) 的数据。本研究旨在确定 IUI 期间 NMSI 是否存在上限，高于该上限会对活产率 (LBR) 产生负面影响。

 设计

对 2010 年 1 月至 2018 年 7 月期间对 <43 id=134> 100 万女性进行的自体 IUI 周期进行回顾性分析。主要结果是每个 IUI 周期的 LBR 作为 NMSI 的函数。

 结果

总共包括 1017 对夫妇进行的 2592 个 IUI 周期。 LBR 随着 NMSI 增加至 3000 万，没有任何上限（AUC = 0.5441）。对于>1至≤10、>10至≤20和>20至≤3000万的NMSI，每个IUI周期的LBR分别为14.5%、17.9%和22.7%（ P = 0.003）。通过单变量分析，NMSI、女性年龄、成熟卵泡数量和排卵触发日雌二醇浓度、周期数和不孕病因影响 LBR。多变量分析显示，当 NMSI >10 至 ≤2000 万（比值比 [OR] 1.49；95% 置信区间 [CI] 1.10–2.02]）和 >20 至 ≤ 进行 IUI 时，LBR 分别高出 1.49 和 1.78 倍。与 NMSI >1 至 ≤1000 万的 IUI 相比，分别为 3000 万（OR 1.78；95% CI 1.08–2.94）。

 结论

IUI 后的 LBR 可以通过最多 3000 万个活动精子的授精来优化。因此，在这个特定队列中，当获得超过 1000 万个活动精子时，不应稀释 IUI 制剂。