Semen quality and prediction of IUI success in male subfertility: a systematic review

Abstract

Many variables may influence success rates after intrauterine insemination (IUI), including sperm quality in the native and washed semen sample. A literature search was performed to investigate the threshold levels of sperm parameters above which IUI pregnancy outcome is significantly improved and/or the cut-off values reaching substantial discriminative performance in an IUI programme. A search of MEDLINE, EMBASE and Cochrane Library revealed a total of 983 papers. Only 55 studies (5.6%) fulfilled the inclusion criteria and these papers were analysed. Sperm parameters most frequently examined were: (i) inseminating motile count after washing: cut-off value between 0.8 and 5 million; (ii) sperm morphology using strict criteria: cut-off value ⩾5% normal morphology; (iii) total motile sperm count in the native sperm sample: cut-off value of 5-10 million; and (iv) total motility in the native sperm sample: threshold value of 30%. The results indicate a lack of prospective studies, a lack of standardization in semen testing methodology and a huge heterogeneity of patient groups and IUI treatment strategies. More prospective cohort trials and prospective randomized trials investigating the predictive value of semen parameters on IUI outcome are urgently needed. It is generally believed that intrauterine insemination (IUI) with homologous semen should be a first-choice treatment to more invasive and expensive techniques of assisted reproduction in cases of cervical, unexplained and moderate male factor subfertility. The rationale for the use of artificial insemination is to increase gamete density at the site of fertilization. Scientific validation of this strategy is difficult because literature is rather confusing and inconclusive. Many variables may influence success rates after IUI treatment procedures. It seems logical that sperm quality has to be one of the main determinants to predict IUI success. Clinical practice would benefit from the establishment of threshold levels for sperm parameters above which IUI pregnancy outcome is significantly improved and below which a successful outcome is unlikely. We performed a literature search to investigate if such threshold levels are known. Most striking were the lack of standardization in semen-testing methodology and the huge heterogeneity of patient groups and IUI treatment strategies. The four sperm parameters most frequently examined were: (i) inseminating motile count after washing: cut-off value between 0.8 and 5 million; (ii) sperm morphology using strict criteria: cut-off value >4% normal morphology; (iii) total motile sperm count in native sperm sample: cut-off value of 5-10 million; and (iv) total motility in native sperm sample: threshold value of 30%. This review identified an urgent need for more and better prospective cohort trials investigating the predictive value of semen parameters on IUI pregnancy rate.

Guidance and Self‐Sorting of Active Swimmers: 3D Periodic Arrays Increase Persistence Length of Human Sperm Selecting for the Fittest

“…The studied correlation of sperm morphology with fertility links abnormal sperm shape to reduced oocyte fertilization for in vitro fertilization 42, 43. However, other correlations, such as the relationship between the shape of sperm and natural conception rates, have been much harder to demonstrate 44, 45. This microfluidic study offers new evidence that sperm morphology is indeed a significant factor in sperm transport in vitro.…”

“…To understand sperm motility in such complex geometries, many hydrodynamic models have been developed at different scales;35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45 however, to the best of our knowledge, no models exist that can bridge the necessary time and length scales to allow the modeling of clinically relevant microfluidic ARTs and improve their design parameters. Here, we designed a filter‐like microfluidic path using multiscale computer simulations in conjunction with experiments and examined how this artificial path of pillars interact with known descriptive and functional characteristics of human sperm, including sperm motility, morphology, DNA integrity, and methylome status.…”

Factors Leading to Pregnancies in Stimulated Intrauterine Insemination Cycles and the Use of Consecutive Ejaculations Within a Small Clinic Environment

“…When it came to male factor consideration, attaining 5 million motile sperm threshold for IUI is recommended [21,28], while there is no consensus on a lower limit of semen quality at which one would advocate IUI [29];the systematic review confirms favourable correlation with IUI success in the range of 5-10 million [30].…”

How to Perform the Best Intrauterine Insemination? A Review

“…It must be remembered that Total Motile Sperm Count [TMSC] inseminated has been cited as the most predictive index of conception after IUI cycles [9][10][11]. A minimalTMSC of 1 million for insemination was initially reported to be a requirement for pregnancy after insemination [12], but the systematic review of the literature by Ombelet et al in 2014 indeed confirms that the native sperm TMSC which shows the best correlation with IUI success is in the range of 5-10 million [6,[13][14][15][16]. According to a previous study, sperm concentration above 10 million is not related to further improvement in conception rates [12], while other investigators have reported the best pregnancy rates when more than 10 million motile spermatozoa are inseminated [9,17].…”

“…Intrauterine Insemination [IUI] is considered the simplest and least invasive procedure with reasonable live birth rates and not needing expensive infrastructure [1]. Inseminations have been done in domestic and farm animals since the 1900's while human artificial inseminations began in the 1940's [2].…”