title: The effect of slow release insemination on pregnancy rates: report of two randomized controlled pilot studies and meta-analysis.
abstract: OBJECTIVE
  A 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.
  
  
  METHODS
  To 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.
  
  
  RESULTS
  Fifty 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).
  
  
  CONCLUSIONS
  In conclusion, these results lend support to the hypothesis that the pregnancy rate might be improved by SRI compared to the standard bolus technique.
authors.affiliation: Department of Obstetrics and Gynecology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: Julian
authors.initials: J
authors.lastname: Marschalek
authors.affiliation: Department of Obstetrics and Gynecology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Franz
authors.affiliation: Lin Medical Center, Haifa, Israel.
authors.forename: Yael
authors.initials: Y
authors.lastname: Gonen
authors.affiliation: Department of Obstetrics and Gynecology, Interdisciplinary Center for Reproductive Medicine (UniKiD), University of Düesseldorf, Düesseldorf, Germany.
authors.forename: Jan-Steffen
authors.initials: JS
authors.lastname: Kruessel
authors.affiliation: Aqueduct Medical Ltd., Nazareth, Israel.
authors.forename: Amnon
authors.initials: A
authors.lastname: Weichselbaum
authors.affiliation: Department of Obstetrics and Gynecology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Kuessel
authors.affiliation: Department of Obstetrics and Gynecology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Trofaier
authors.affiliation: Department of Obstetrics and Gynecology, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria. johannes.ott@meduniwien.ac.at.
authors.forename: Johannes
authors.initials: J
authors.lastname: Ott
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D005260:Female; D005307:Fertilization in Vitro; D005858:Germany; D006801:Humans; D007315:Insemination, Artificial / Q000295:instrumentation / Q000379:methods*; D007557:Israel; D008297:Male; D010865:Pilot Projects; D011247:Pregnancy; D018873:Pregnancy Rate; D011897:Random Allocation; D013094:Spermatozoa; D013997:Time Factors
keywords: Infertility; Intrauterine insemination; Outcome; Pregnancy rate; Slow release insemination