Unexplained Total Fertilization Failure after Intracytoplasmic Sperm Injection Cycles: A Case-Control Study on Predictive Factors and Retreatment Prognosis

Document Type : Original Article


1 1. Department of Endocrinology and Female Infertility, Reproductive Biomedicine Research Center, Royan Institute for reproductive biomedicine, ACECR, Tehran, Iran

2 2. Department of Epidemiology and Reproductive Health, Reproductive Epidemiology Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran

3 Department of Diabetes, Obesity and Metabolism, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran



Background: Here, we intend to detect the rate of unexplained total fertilization failure (TFF) after intracytoplasmic sperm injection (ICSI) and identify its risk factors and retreatment prognosis.
Materials and Methods: In this retrospective case-control study, we searched the computerized database of Royan Institute (Tehran, Iran) from March 2015 to March 2019 and retrieved all cases diagnosed with TFF after ICSI. TFF cases that did not have any recognized risk factors were classified as unexplained (subgroup A). Cases with recognized risk factors were classified as subgroup B. The control group was randomly selected among the infertile couples who underwent ICSI cycles with fertilization of at least one oocyte during the same time interval. The characteristics and treatment outcomes of the cases with unexplained TFF (subgroup A) were compared with their control group, and with the other TFF cases (subgroup B).
Results: In total, out of 18 750 couples who underwent ICSI cycles, 296 (1.5%) couples experienced TFF for the first time. Of these 296 couples, 49 (16.5%) cases were diagnosed with unexplained TFF (subgroup A) and 247 (83.5%) were placed in subgroup B, TFF with expected risk factors. Multivariable logistic regression analysis results showed that the total number of mature oocytes (P<0.001), duration of infertility (P=0.043), and women’s body mass index (BMI) (P<0.001) were significantly predictive factors for unexplained TFF. In the ICSI cycle after TFF, the clinical pregnancy and live birth rates in subgroup A were higher than subgroup B. Although the differences between these groups were not statistically significant (P=0.14 and P=0.07, respectively), this finding could be clinically important.
Conclusion: Unexplained TFF following ICSI is a rare event significantly related to female factors and has a good prognosis in retreatment cycles in comparison with expected TFF cases. Therefore, clinicians should take this into consideration for patient counseling and management.


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