Objective:To explore the cause of abnormal morphology sperm on fertilization from insemination function and provide reference for the selection of fertilization methods for teratozoospermia patients.Methods:Through a retrospective cohort study of their first in vitro fertilization (IVF) treatment cycles in Reproductive Medicine Center of Shenzhen People's Hospital from January 2016 to March 2020, all patients were divided into four groups according to the normal sperm morphology rate (NSMR), group A: IVF normal sperm morphology (NSMR≥4%, n=750), group B:mild teratozoospermia (2%≤NSMR<4%, n=277), group C: moderate teratozoospermia (1%≤NSMR<2%, n=110), group D: severe teratozoospermia (0%≤NSMR<1%, n=49). We compared normal fertilization rate, fertilization failure rate (fertilization rate<30%) and total fertilization failure rate (fertilization rate=0) among the four groups and we also compared insemination function indexs: 2 h tyrosine phosphorylation rate, hyaluronan-binding assay (HBA) positive rate, content of acrosin, spontaneous acrosome reaction rate and induced acrosome reaction rate. Results:1) The normal fertilization rate of group D [52.4%(18.3%, 69.0%)] was significantly lower than that of group A [60.0%(45.5%, 75.0%), P=0.008] and group B [60.0%(42.9%, 75.0%), P=0.028]; the fertilization failure rate [22.4% (11/49)] was significantly higher than that of group A [5.5% (41/750), P<0.001] and group B [8.3% (23/277), P=0.018]; the total fertilization failure rate [14.3% (7/49)] was significantly higher than that of group A [2.7% (20/750), P=0.006]. Multivariate logistic regression models: the normal fertilization rate of group D was significantly lower than that of group A ( OR=0.433, P=0.008), and the risk of fertilization failure ( OR=5.426, P<0.001) and total fertilization failure ( OR=8.194, P<0.001) were significantly higher than those of group A. 2) HBA positive rate in groups B, C, D [75.0%(62.3%, 83.0%), 71.0%(58.0%, 81.0%), 68.0%(48.0%, 76.5%)] was significantly lower than that in group A [80.0%(71.0%, 85.0%), all P<0.001] and induced acrosome reaction rate in group C and group D [32.3%(26.5%, 40.8%), 28.8%(24.2%, 43.0%)] was significantly lower than that in group A [37.8%(30.5%, 46.8%), P<0.001, P=0.009]. 3) Spearman correlation analysis showed that spem normal morphology rate was positively correlated with HBA positive rate ( r=0.259, P<0.001) and induced acrosome reaction rate ( r=0.202, P<0.001). 4) Receiver operating characteristic (ROC) curve analysis was performed to determine a cut-off value using HBA positive rate, induced acrosome reaction rate and sperm normal morphology rate as independent variables with the fertilization rate of IVF cycles (normal sperm morphology rate <4%) dichotomized at 30%. The best cut-off value of HBA positive rate obtained was 73.5% with a sensitivity of 51.4% and specificity of 73.8% [area under curve (AUC) (95% CI)=0.643 (0.559-0.726), P=0.002]; the cut-off value of induced acrosome reaction rate was 28.9% with a sensitivity of 72.1% and specificity of 50% [AUC (95% CI)=0.599 (0.497-0.700), P=0.036]; the cut-off value of normal sperm morphology rate was 1.45% with a sensitivity of 77.8% and specificity of 42.9% [AUC (95% CI)=0.605 (0.509-0.701), P=0.025]. Conclusion:Abnormal morphology sperm may affect IVF fertilization by HBA positive rate and induced acrosome reaction rate. For teratozoospermia patients, especially for the severe teratozoospermia (0%≤NSMR<1%), we recommend that HBA positive rate and induced acrosome reaction rate are tested after ovulation induction treatment. If the post-treatment sperm meets the requirements of routine IVF fertilization on the day of retrieved oocytes, but HBA positive rate<73.5%, induced acrosome reaction rate<28.9%, short time IVF or intracytoplasmic sperm injection (ICSI) or half-ICSI is recommended to minimize IVF fertilization failure.

Objective:To explore the cause of abnormal morphology sperm on fertilization from insemination function and provide reference for the selection of fertilization methods for teratozoospermia patients.Methods:Through a retrospective cohort study of their first in vitro fertilization (IVF) treatment cycles in Reproductive Medicine Center of Shenzhen People's Hospital from January 2016 to March 2020, all patients were divided into four groups according to the normal sperm morphology rate (NSMR), group A: IVF normal sperm morphology (NSMR≥4%, n=750), group B:mild teratozoospermia (2%≤NSMR<4%, n=277), group C: moderate teratozoospermia (1%≤NSMR<2%, n=110), group D: severe teratozoospermia (0%≤NSMR<1%, n=49). We compared normal fertilization rate, fertilization failure rate (fertilization rate<30%) and total fertilization failure rate (fertilization rate=0) among the four groups and we also compared insemination function indexs: 2 h tyrosine phosphorylation rate, hyaluronan-binding assay (HBA) positive rate, content of acrosin, spontaneous acrosome reaction rate and induced acrosome reaction rate. Results:1) The normal fertilization rate of group D [52.4%(18.3%, 69.0%)] was significantly lower than that of group A [60.0%(45.5%, 75.0%), P=0.008] and group B [60.0%(42.9%, 75.0%), P=0.028]; the fertilization failure rate [22.4% (11/49)] was significantly higher than that of group A [5.5% (41/750), P<0.001] and group B [8.3% (23/277), P=0.018]; the total fertilization failure rate [14.3% (7/49)] was significantly higher than that of group A [2.7% (20/750), P=0.006]. Multivariate logistic regression models: the normal fertilization rate of group D was significantly lower than that of group A ( OR=0.433, P=0.008), and the risk of fertilization failure ( OR=5.426, P<0.001) and total fertilization failure ( OR=8.194, P<0.001) were significantly higher than those of group A. 2) HBA positive rate in groups B, C, D [75.0%(62.3%, 83.0%), 71.0%(58.0%, 81.0%), 68.0%(48.0%, 76.5%)] was significantly lower than that in group A [80.0%(71.0%, 85.0%), all P<0.001] and induced acrosome reaction rate in group C and group D [32.3%(26.5%, 40.8%), 28.8%(24.2%, 43.0%)] was significantly lower than that in group A [37.8%(30.5%, 46.8%), P<0.001, P=0.009]. 3) Spearman correlation analysis showed that spem normal morphology rate was positively correlated with HBA positive rate ( r=0.259, P<0.001) and induced acrosome reaction rate ( r=0.202, P<0.001). 4) Receiver operating characteristic (ROC) curve analysis was performed to determine a cut-off value using HBA positive rate, induced acrosome reaction rate and sperm normal morphology rate as independent variables with the fertilization rate of IVF cycles (normal sperm morphology rate <4%) dichotomized at 30%. The best cut-off value of HBA positive rate obtained was 73.5% with a sensitivity of 51.4% and specificity of 73.8% [area under curve (AUC) (95% CI)=0.643 (0.559-0.726), P=0.002]; the cut-off value of induced acrosome reaction rate was 28.9% with a sensitivity of 72.1% and specificity of 50% [AUC (95% CI)=0.599 (0.497-0.700), P=0.036]; the cut-off value of normal sperm morphology rate was 1.45% with a sensitivity of 77.8% and specificity of 42.9% [AUC (95% CI)=0.605 (0.509-0.701), P=0.025]. Conclusion:Abnormal morphology sperm may affect IVF fertilization by HBA positive rate and induced acrosome reaction rate. For teratozoospermia patients, especially for the severe teratozoospermia (0%≤NSMR<1%), we recommend that HBA positive rate and induced acrosome reaction rate are tested after ovulation induction treatment. If the post-treatment sperm meets the requirements of routine IVF fertilization on the day of retrieved oocytes, but HBA positive rate<73.5%, induced acrosome reaction rate<28.9%, short time IVF or intracytoplasmic sperm injection (ICSI) or half-ICSI is recommended to minimize IVF fertilization failure.