The effect of slow release insemination on pregnancy rates: report of two randomized controlled pilot studies and meta-analysis

Abstract

PurposeA modified application technique of intrauterine insemination (IUI) is slow release insemination (SRI), first described by Muharib et al. (Hum Reprod 7(2):227–229, 1992), who postulated higher pregnancy rates with a slow release of spermatozoa for 3 h.MethodsTo investigate this approach, two randomized controlled, cross-over pilot studies were performed from 2004 to 2006 in Israel and Germany to compare SRI with the standard bolus IUI. We aimed to present the results and perform a meta-analysis on available data for SRI. Univariate comparisons of pregnancy rates were performed using one-tailed z tests for method superiority. For meta-analysis, a fixed-effect Mantel–Haentzel weighted average of relative risk was performed.ResultsFifty treatment cycles (IUI: n = 25, SRI: n = 25) were performed in Germany, achieving four pregnancies (IUI: 4%, SRI: 12%, p > 0.05). Thirty-nine treatment cycles (IUI: n = 19, SRI: n = 20) were performed in Israel achieving six pregnancies (IUI: 10.5%, SRI: 20%; p > 0.05). Meta-analysis of all eligible studies for SRI (n = 3) revealed a combined relative risk for pregnancy after SRI of 2.64 (95% CI 1.04–6.74), p = 0.02).ConclusionsIn conclusion, these results lend support to the hypothesis that the pregnancy rate might be improved by SRI compared to the standard bolus technique.

Intrauterine Insemination: Fundamentals Revisited

“…Metaanalysis of all eligible studies for SRI (n = 3) revealed a combined relative risk for pregnancy after SRI of 2.64 (95% CI 1.04-6.74), P = 0.02). In conclusion, these results lend support to the hypothesis that the pregnancy rate might be improved by SRI compared to the standard bolus technique [39].…”

“…Marschalek et al aimed to present the results and perform a meta-analysis on available data for SRI [39]. Univariate comparisons of pregnancy rates were performed using one-tailed z tests for method superiority.…”

Pregnancy rates after slow-release insemination (SRI) and standard bolus intrauterine insemination (IUI) – A multicentre randomised, controlled trial

“…This multicentre, randomised, controlled cross-over trial was conducted in women with infertility and/or the need for semen donation who were eligible for IUI in 11 fertility centres across Europe. As already stated in a prior pilot study 22 , the cross-over design was chosen because it has been shown to give results comparable to those from studies with a parallel design, and, thus, to be a valid approach for infertility trials 23,24 .…”

“…Patients were recruited between October 2012 and June 2017. Women were included if they fulfilled all of the following criteria: 22 (i) primary or secondary infertility, defined as a couple's failure to conceive after 12 months of attempting conception; (ii) age 20-40 years; (iii) tubal patency as diagnosed by hysterosalpingography, hystero-contrast-sonography (hycosy) or dye test with a maximum time interval between tubal testing and the woman's enrolment into the study of 12 months; (iv) since the total motile sperm count is a major factor which influences pregnancy changes after IUI 25 , a minimum of 10 million motile sperm cells/ millilitre (mio/ml) after preparation; (v) infertility due to anovulation and/or endometriosis and/or the need for semen donation and/or unexplained infertility. In this context, unexplained infertility is defined as the absence of a definable reason for a couple's failure to conceive after 12 months of attempting conception despite a detailed evaluation of ovulation, tubal and uterine abnormalities and male infertility factors.…”

“…The authors hypothesised that a persistent low concentration of spermatozoa might prolong the period of potential fertilisation and thereby mimic physiological sperm transportation from the cervix to the fallopian tube. We have recently published data from two pilot randomised, controlled cross-over studies that indicate a statistically significant advantage of SRI over conventional bolus IUI 22 . The present, larger, multicentre trial was performed to clarify the effect of intra-uterine SRI on pregnancy rates in women designated for standard bolus IUI.…”