title: Does reducing gamete co-incubation time improve clinical outcomes: a retrospective study.
abstract: OBJECTIVE
  The objective of this retrospective study was to determine whether patients undergoing in vitro fertilization (IVF) benefit from reducing the gamete co-incubation time.
  
  
  METHODS
  Patients (n = 570) were enrolled, including 281 patients in the reduced incubation time group (2-h incubation) and 289 patients in the standard IVF group (18-h incubation).
  
  
  RESULTS
  The observed outcomes, including the clinical pregnancy rate (CPR), implantation rate (IR), live birth rate (LBR), and miscarriage rate (MR), were similar between the two groups. When the data were divided into two subgroups based on the maternal age (≤30 and >30 years), the rates of top-quality embryos (30.83 vs. 25.89 %; p = 0.028), CPR (66.67 vs. 42.11 %; p = 0.013), and IR (41.90 vs. 31.25 %, p = 0.019) of the 2-h incubation group were significantly higher in the younger subgroup. However, for older patients, only a lower MR (7.59 vs. 20.83 %; p = 0.019) was achieved. Reducing the time of incubation still improved the CPR (OR = 1.993, 95 % CI 1.141-3.480) and MR (OR = 3.173, 95 % CI 1.013-9.936) in the younger and older subgroups, respectively, after it was adjusted for potential confounders.
  
  
  CONCLUSIONS
  Reducing incubation time improves the clinical results of IVF, although the LBR is not statistically different between the 2- and 18-h incubation time groups. And the specific clinical outcomes of reducing incubation time varied between the >30-year-old and the ≤30-year-old.
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. lirq07@sina.com.|Department of Obstetrics and Gynecology, Reproductive Medicine Centre, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. lirq07@sina.com.
authors.forename: Rui-Qi
authors.initials: RQ
authors.lastname: Li
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. 563667624@qq.com.|Department of Obstetrics and Gynecology, Reproductive Medicine Centre, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. 563667624@qq.com.
authors.forename: Neng-Yong
authors.initials: NY
authors.lastname: Ouyang
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. 195815612@qq.com.|Department of Obstetrics and Gynecology, Reproductive Medicine Centre, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. 195815612@qq.com.
authors.forename: Song-Bang
authors.initials: SB
authors.lastname: Ou
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. lilyni66@126.com.|Department of Obstetrics and Gynecology, Reproductive Medicine Centre, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. lilyni66@126.com.
authors.forename: Ren-Min
authors.initials: RM
authors.lastname: Ni
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. wxszzx@163.com.|Department of Obstetrics and Gynecology, Reproductive Medicine Centre, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. wxszzx@163.com.
authors.forename: Mei-Qi
authors.initials: MQ
authors.lastname: Mai
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. zhangqingxue666@aliyun.com.|Department of Obstetrics and Gynecology, Reproductive Medicine Centre, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. zhangqingxue666@aliyun.com.
authors.forename: Qing-Xue
authors.initials: QX
authors.lastname: Zhang
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. yangdz@mail.sysu.edu.cn.|Department of Obstetrics and Gynecology, Reproductive Medicine Centre, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. yangdz@mail.sysu.edu.cn.
authors.forename: Dong-Zi
authors.initials: DZ
authors.lastname: Yang
authors.affiliation: Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. wenjungzcn@163.com.|Department of Obstetrics and Gynecology, Reproductive Medicine Centre, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China, 510120. wenjungzcn@163.com.
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Wang
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology; D000328:Adult; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000379:methods; D005260:Female; D005307:Fertilization in Vitro; D005854:Germ Cells / Q000254:growth & development*; D006801:Humans; D050498:Live Birth / Q000453:epidemiology; D008423:Maternal Age; D011247:Pregnancy; D018873:Pregnancy Rate
keywords: Fertility; Gamete co-incubation; Live birth rate; Miscarriage rate