Effect of heat-induced hypermotility on pregnancy rate in intrauterine insemination for male factor infertility associated with asthenospermia: a prospective, randomized, controlled study

Semen preparation techniques for intrauterine insemination

BACKGROUND

Semen preparation techniques for assisted reproduction, including intrauterine insemination (IUI), were developed to select the motile morphologically normal spermatozoa. The yield of many motile, morphologically normal spermatozoa might influence treatment choices and therefore outcomes.

OBJECTIVES

To compare the effectiveness of three different semen preparation techniques (gradient; swim-up; wash and centrifugation) on clinical outcomes (live birth rate; clinical pregnancy rate) in subfertile couples undergoing IUI.

SEARCH METHODS

We searched the Cochrane Gynaecology and Fertility Group (CGFG) trials register, CENTRAL, MEDLINE, Embase, Science Direct Database, National Research Register, Biological Abstracts and clinical trial registries in March 2019, and checked references and contacted study authors to identify additional studies.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures recommended by Cochrane. The primary review outcomes are live birth rate and clinical pregnancy rate per couple.

MAIN RESULTS

We included seven RCTS in the review; we included six of these, totalling 485 couples, in the meta-analysis. No trials reported the primary outcome of live birth. The evidence was of very low-quality. The main limitations were (unclear) risk of bias, signs of imprecision and inconsistency in results among studies and the small number of studies/participants included.Swim-up versus gradient technique Considering the quality of evidence, we are uncertain whether there was a difference between clinical pregnancy rates (CPR) for swim-up versus a gradient technique (odds ratio (OR) 0.83, 95% CI 0.51 to 1.35; I² = 71%; 4 RCTs, 370 participants; very low-quality evidence). The results suggest that if the chance of pregnancy after the use of a gradient technique is assumed to be 24%, the chance of pregnancy after using the swim-up technique is between 14% and 30%. We are uncertain whether there was a real difference between ongoing pregnancy rates per couple (OR 0.39, 95% CI 0.19 to 0.82; heterogeneity not applicable; 1 RCT, 223 participants; very low-quality evidence). Considering the quality of evidence, we are uncertain whether there was a difference between multiple pregnancy rates (MPR) per couple comparing a swim-up versus gradient technique (MPR per couple 0% versus 0%; 1 RCT, 25 participants; very low-quality of evidence). Considering the quality of evidence, we are also uncertain whether there was a difference between miscarriage rates (MR) per couple comparing a swim-up versus gradient technique (OR 0.85, 95% CI 0.28 to 2.59; I² = 44%; 3 RCTs, 330 participants; very low-quality evidence). No studies reported on ectopic pregnancy rate, fetal abnormalities or infection rate.Swim-up versus wash techniqueConsidering the quality of evidence, we are uncertain whether there is a difference in clinical pregnancy rates after a swim-up technique versus wash and centrifugation (OR 0.41, 95% CI 0.15 to 1.13; I² = 55%; 2 RCTs, 78 participants; very low-quality evidence). The results suggest that if the chance of pregnancy after the use of a wash technique is assumed to be 38%, the chance of pregnancy after using the swim-up technique is between 9% and 41%. Considering the quality of evidence, we are uncertain whether there was a difference between multiple pregnancy rates between swim-up technique versus wash technique (OR 0.49, 95% CI 0.02 to 13.28; heterogeneity not applicable; 1 RCT, 26 participants; very low-quality evidence). Miscarriage rate was only reported by one study: no miscarriages were reported in either treatment arm. No studies reported on ongoing pregnancy rate, ectopic pregnancy rate, fetal abnormalities or infection rate.Gradient versus wash techniqueConsidering the quality of evidence, we are uncertain whether there is a difference in clinical pregnancy rates after a gradient versus wash and centrifugation technique (OR 1.78, 95% CI 0.58 to 5.46; I² = 52%; 2 RCTs, 94 participants; very low-quality evidence). The results suggest that if the chance of pregnancy after the use of a wash technique is assumed to be 13%, the chance of pregnancy after using the gradient technique is between 8% and 46%. Considering the quality of evidence, we are uncertain whether there was a difference between multiple pregnancy rates per couple between the treatment groups (OR 0.33, 95% CI 0.01 to 8.83; very low-quality evidence). Considering the quality of evidence, we are also uncertain whether there was a difference between miscarriage rates per couple between the treatment groups (OR 6.11, 95% CI 0.27 to 138.45; very low-quality evidence). No studies reported on ongoing pregnancy rate, ectopic pregnancy rate, fetal abnormalities or infection rate.

AUTHORS' CONCLUSIONS

There is insufficient evidence to recommend any specific semen preparation technique: swim-up versus gradient versus wash and centrifugation technique. No studies reported on live birth rates. Considering the quality of evidence (very low), we are uncertain whether there is a difference in clinical pregnancy rates, ongoing pregnancy rates, multiple pregnancy rates or miscarriage rates per couple) between the three sperm preparation techniques. Further randomised trials are warranted that report live birth data.

The effect of preserving prepared sperm samples at room temperature or at 37 °C before intrauterine insemination (IUI) on clinical pregnancy rate

OBJECTIVE

The comparison of the effect of preserving prepared sperm samples at room temperature or at 37 °C before intrauterine insemination (IUI) on clinical pregnancy rate.

MATERIALS AND METHODS

Retrospective clinical research. University hospital, infertility clinic. Patients with one or two follicles, between the ages of 20 and 40, whose infertility period was less than 6 years and the injected total motile sperm count was more than 10 million. Preserving sperm samples prepared for IUI at 37 ºC or at room temperature before IUI. The clinical pregnancy rate of IUI cycles between 1^st of January 2004 and 1^st of December 2011 in which prepared sperm samples were preserved at 37 ºC and the clinical pregnancy rate of IUI cycles between 1^st of December 2011 and 31^st of May 2014 in which prepared sperm samples preserved at room temperature.

RESULTS

Clinical pregnancy rates were similar in IUI cycles in which prepared sperm samples were preserved at 37 ºC and at room temperature (9.3% vs. 8.9%). Clinical pregnancy rates in IUI cycles with 2 follicles were higher than IUI cycles with 1 follicle (10.8% vs. 7.6%) (p=0.002). Further statistical analysis after splitting data according to the number of the follicles revealed that there was no statistical difference between clinical pregnancy rates after IUI cycles in which prepared sperm samples were preserved at 37 ºC or at room temperature in both one follicle (7.6% vs. 7.6%), and two follicle cycles (11.5% vs. 10.1%).

CONCLUSIONS

Preserving prepared sperm samples at room temperature had no negative effect on clinical pregnancy rates when compared with reserving prepared sperm samples at 37 ºC during IUI cycles.

Thermotaxis of human sperm cells in extraordinarily shallow temperature gradients over a wide range

On the basis of the finding that capacitated (ready to fertilize) rabbit and human spermatozoa swim towards warmer temperatures by directing their movement along a temperature gradient, sperm thermotaxis has been proposed to be one of the processes guiding these spermatozoa to the fertilization site. Although the molecular mechanism underlying sperm thermotaxis is gradually being revealed, basic questions related to this process are still open. Here, employing human spermatozoa, we addressed the questions of how wide the temperature range of thermotaxis is, whether this range includes an optimal temperature or whether spermatozoa generally prefer swimming towards warmer temperatures, whether or not they can sense and respond to descending temperature gradients, and what the minimal temperature gradient is to which they can thermotactically respond. We found that human spermatozoa can respond thermotactically within a wide temperature range (at least 29–41°C), that within this range they preferentially accumulate in warmer temperatures rather than at a single specific, preferred temperature, that they can respond to both ascending and descending temperature gradients, and that they can sense and thermotactically respond to temperature gradients as low as <0.014°C/mm. This temperature gradient is astonishingly low because it means that as a spermatozoon swims through its entire body length (46 µm) it can sense and respond to a temperature difference of <0.0006°C. The significance of this surprisingly high temperature sensitivity is discussed.

The role of intrauterine insemination in male infertility

Male infertility is a common condition and intrauterine insemination (IUI) is used to treat the mild to moderate forms. Male subfertility determination is usually based on routine semen analysis but recent publications have questioned its diagnostic and prognostic accuracy as well as the effectiveness of IUI itself, as a treatment modality. We carried out a structured review of the literature to assess the current evidence regarding the diagnosis of male infertility, the effectiveness and cost effectiveness of IUI in male infertility and factors that affect the outcome of IUI. There is still uncertainty regarding the criteria for diagnosing male infertility and predicting treatment outcome based on standard semen parameters. The presence of seminal defects compromises the outcome of IUI in comparison with unexplained infertility. The total motile sperm count (TMSC) appears to have a consistent, direct relationship with treatment outcome, but there is no definite predictive threshold for success. However, it is reasonable to offer IUI as first-line treatment if TMSC is greater than 10 million when balancing the risk and cost of alternate treatments, such as in vitro fertilization (IVF). Sperm DNA studies and sperm preparation techniques warrant further studies in order to establish their clinical relevance. There are limited data on the clinical and cost-effectiveness of IUI in male infertility and large high-quality randomized controlled trials are warranted. However the difficulties in organizing such a study, at the present time, are a matter for discussion.

Semen preparation techniques for intrauterine insemination

BACKGROUND

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

OBJECTIVES

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

SEARCH STRATEGY

We searched the Menstrual Disorders and Subfertility Group Trials Register (13 January 2007), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 2), MEDLINE (1966 to January 2007 ), EMBASE (1980 to January 2007), Science Direct Database (1966 to January 2007), National Research Register (2000 to 2007), Biological Abstracts (2000 to January 2007), CINAHL (1982 to October 2006) and reference lists of relevant articles. We also contacted experts and authors in the field.

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

Two reviewer 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 compared the three techniques; Soliman compared a gradient technique versus a wash technique; Dodson and Posada compared a gradient technique versus a swim-up technique; whereas Grigoriou 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 or wash and centrifugation technique (Peto OR 1.57, 95% CI 0.74 to 3.32; Peto OR 0.41, 95% CI 0.15 to 1.10, respectively); nor in the two studies comparing a gradient technique versus wash and centrifugation (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 swim-up versus a gradient technique (Peto OR 0.13, 95% CI 0.01 to 1.33).

AUTHORS' CONCLUSIONS

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