Semen preparation techniques for intrauterine insemination

The effectiveness of specific semen preparation techniques for increasing pregnancy rates in subfertile couples undergoing intrauterine insemination (IUI) is unknown.

Semen preparation techniques are used in assisted reproduction to separate sperm which have a normal appearance and move spontaneously from the fluid portion of the semen in which the sperm are suspended. It is known that white blood cells, bacteria and dead sperm in semen can impair fertilization of the egg. This review found that there is insufficient evidence to recommend any specific semen preparation technique for subfertile couples undergoing intrauterine insemination (a procedure which places sperm directly into the uterus) as there were no differences in pregnancy rates using the different techniques. More research is needed.

Authors' conclusions: 

There is insufficient evidence to recommend any specific semen preparation technique. Large, high quality randomised controlled trials comparing the effectiveness of a gradient, swim-up and wash and centrifugation technique on clinical outcomes are lacking. Further randomised trials are warranted.

Read the full abstract...

Semen preparation techniques for assisted reproduction, including intrauterine insemination (IUI), were developed to separate the motile morphologically normal spermatozoa. Leucocytes, bacteria and dead spermatozoa produce oxygen radicals that negatively influence the ability to fertilize the egg. The yield of many motile, morphologically normal spermatozoa might influence treatment choices and therefore outcomes.


To compare the effectiveness of gradient, swim-up, or wash and centrifugation semen preparation techniques on clinical outcomes in subfertile couples undergoing intrauterine insemination (IUI).

Search strategy: 

We searched the Menstrual Disorders and Subfertility Group Trials Register (August 2011), MEDLINE (1966 to August 2011), EMBASE (1980 to August 2011), Science Direct Database (1966 to August 2011), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 7), National Research Register (2000 to 2011), Biological Abstracts (2000 to August 2011), CINAHL (1982 to August 2011) and reference lists of relevant articles. We also contacted experts and authors in the field.

Selection criteria: 

Randomised controlled trials (RCTs) comparing the efficacy of semen preparation techniques used for subfertile couples undergoing IUI in terms of clinical outcomes were included.

Data collection and analysis: 

Two review authors independently assessed trial quality and extracted data. Study authors were contacted for additional information.

Main results: 

Five RCTs, including 262 couples in total, were included in the meta-analysis (Dodson 1998; Grigoriou 2005; Posada 2005; Soliman 2005; Xu 2000). Xu 2000 compared all three techniques. Soliman 2005 compared a gradient versus a wash technique. Dodson 1998 and Posada 2005 compared a gradient technique versus a swim-up technique, whereas Grigoriou 2005 compared swim-up versus a wash technique. No trials reported the primary outcome of live birth.

There was no evidence of a difference between pregnancy rates (PR) for swim-up versus a gradient technique (PR 30.5% versus 21.5% respectively; Peto odds ratio (OR) 1.57, 95% CI 0.74 to 3.32). A swim-up technique versus wash and centrifugation also showed no significant difference in PR (PR 22.2% versus 38.1% respectively; Peto OR 0.41, 95% CI 0.15 to 1.10). Two studies compared a gradient versus wash centrifugation technique (PR 23.5% versus 13.3%; Peto OR 1.76, 95% CI 0.57 to 5.44). There was no evidence of a difference in the miscarriage rate (MR) in two studies comparing a swim-up versus gradient technique (MR 0% versus 6.7%; Peto OR 0.13, 95% CI 0.01 to 1.33).

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