title: Fertilization rate and its determinants in intracytoplasmic sperm injection.
abstract: OBJECTIVE
  To identify predictors of fertilization rate in patients of unexplained infertility after intracytoplasmic sperm injection (ICSI).
  
  
  METHODS
  Retrospective analysis of females (282) enrolled in quasi experimental design for ICSI at "Islamabad Clinic Serving Infertile Couples" was carried out from July 2013 till June 2014. Females with unexplained infertility were included, whereas well defined male and female causes of infertility were excluded. Fertilization rate (FR) was calculated as percentage transformation of micro injected oocytes into two pronuclei. Categorical variable of FR defined on the basis of 50% FR grouped females; Group I with FR ≤50% and Group II with FR >50%. The groups were compared in terms of demographic variables, base line hormones and oocyte parameters. Univariate logistic regression was executed to obtain odds ratio with 95% confidence interval to quantify the association of predictors like age, duration of infertility, oocytes parameters, hormones; Estradiol, progesterone, follicle stimulating hormone (FSH), luteinizing hormone, prolactin and cytokines interleukin-Iβ (IL-Iβ) with the FR.
  
  
  RESULTS
  In our study out of 282 females, 19 (6.73%) were in group I and 263 (93.26%) comprised of Group II. Females with high FR(group II) had low Progesterone and FSH (p=0.04, p=0.02) respectively. Mature oocytes (OR: 0.35; 95% CI 1 - 2.56) and IL-Iβ in follicular phase (OR: 1.04; 95% CI: 0.000- 1.20) were significant positive predictors of FR while peak progesterone and FSH had significant negative effect on it.
  
  
  CONCLUSIONS
  Fertilization of oocytes in females of unexplained infertility depended on maturity of oocytes and optimal amounts of ILI- β released by developing follicles in the follicular phase of stimulation cycles of ICSI.
authors.affiliation: Dr. Shireen Jawed, M.Phil Physiology, Assistant Professor of Physiology, Islam Medical & Dental College, Sialkot, Pakistan.
authors.forename: Shireen
authors.initials: S
authors.lastname: Jawed
authors.affiliation: Dr. Rehana Rehman, PhD Physiology, Assistant Professor of Physiology, Aga Khan University, Karachi, Pakistan.
authors.forename: Rehana
authors.initials: R
authors.lastname: Rehman
authors.affiliation: Dr. Mohammad Ashfaq Ali, M.Phil Bio Chemistry, Assistant Professor, Liaquat National Medical College, Karachi, Pakistan.
authors.forename: Mohammad Ashfaq
authors.initials: MA
authors.lastname: Ali
authors.affiliation: Umme Hani Abdullah, Medical student, Aga Khan University, Karachi, Pakistan.
authors.forename: Umme Hani
authors.initials: UH
authors.lastname: Abdullah
authors.affiliation: Hina Gul, Senior Research Analyst, Prontolinks International (Pvt) Ltd, Lahore, Pakistan.
authors.forename: Hina
authors.initials: H
authors.lastname: Gul
keywords: Fertilization; Fertilization rate; Interleukin; Intracytoplasmic sperm injection