en 29062796 <p>Background: The purpose of this study was to evaluate whether clinical pregnancy rate is affected by timing intrauterine insemination (IUI) according to serum LH surge, r-hCG trigger, or a combination of LH surge and r-hCG trigger in controlled ovarian hyperstimulation (COH) cycles for patients with a variety of infertility etiologies.<br /> Methods: The last 365 consecutive COH-IUI cycles performed at ONE Fertility Burlington in 2014 were reviewed and categorized according to method of IUI timing. Associations between categorical variables were analyzed using a combination of Chi-square and Fisher&rsquo;s Exact tests, and between continuous variables using independent sample t-tests and logistic regression to a level of significance of p&lt;0.05.<br /> Results: The overall clinical pregnancy rate in this sample was 18.1% (66/365). Administration of r-hCG prior to IUI resulted in a higher clinical pregnancy rate compared with spontaneous serum LH surge: 18.2% <em>vs</em>. 5.8%, p=0.012. Patients in whom r-hCG was administered concomitantly with a serum LH surge had a higher clinical pregnancy than the r-hCG trigger group (30.8% <em>vs</em>. 18.2%, p=0.004) and LH surge group (30.8% <em>vs</em>. 5.8%, p&lt;0.001). A sub-group analysis revealed that patients receiving r-FSH, rather than clomiphene or letrozole, had a significantly higher clinical pregnancy rate after r-hCG trigger as compared to the LH surge group (21.7% <em>vs</em>. 2.1%, p=0.01).<br /> Conclusion: In subfertile couples undergoing COH-IUI, r-hCG administration was associated with an increased clinical pregnancy rate compared with spontaneous serum LH surge. When r-hCG was administered concomitantly with a serum LH surge, this benefit was amplified. The effect appears to be of particular importance in r-FSH-medicated cycles.</p> Controlled ovarian hyperstimulation, hCG, Infertility, Intra uterine insemination, LH surge, Subfertility 316 323 https://www.jri.ir/article/716 https://www.jri.ir/documents/fullpaper/en/716.pdf EvanTaerkDivision of Gynecologic Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, McMaster University, Hamilton, Ontario, Canadaetaerk@onefertility.com1738EdwardHughesDivision of Gynecologic Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, McMaster University, Hamilton, Ontario, Canada1739CassandraGreenbergDivision of Gynecologic Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, McMaster University, Hamilton, Ontario, Canada1740MichaelNealDivision of Gynecologic Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, McMaster University, Hamilton, Ontario, Canada1741ShilpaAminDivision of Gynecologic Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, McMaster University, Hamilton, Ontario, Canada1742MehrnooshFaghihDivision of Gynecologic Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, McMaster University, Hamilton, Ontario, Canada1743MeganKarnisDivision of Gynecologic Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, McMaster University, Hamilton, Ontario, Canada1744