Factors Relating With Fertilization Failure Or Low Fertilization Rate And Subsequent Treatment Outcomes In Conventional IVF-ET Cycles

Total fertilization failure or low fertilization rate in conventional infertilization(IVF)is inevitable. It not only affects the cycle pregnancy rates, butalso brings mental physical and economic burden to the infertility couples.The factors that cause fertilization failure and low fertilization rate include theinherent qualities of the oocytes and sperm, the vitro environment etc. Somestudies have analyzed the cause of fertilization failure factors in clinicalparameters, molecular biology, immunology and other aspects respectivelys.Some measures have been used in clinical to avoid and prevent the occurrenceof such a situation, such as rescue intracytoplasmic sperm injection(R-ICSI),conventional IVF and ICSI in one cycle (half-ICSI) and Subsequentintracytoplasmic sperm injection. How to prevent and reduce the occurrenceof fertilization failure and to improve the overall outcome of in vitrofertilization has become the primary importance. This study analyzedretrospectively the clinical and laboratory data of the patients with fertilizationfailure and low fertilization rate and the follow-up treatments, in order to findthe relevant factors relating with fertilization failure and low fertilization ratein conventional IVF cycles and evaluate the clinical outcomes with the use ofR-ICSI, half-ICSI, Subsequent ICSI.Part ⅠFactors relating with fertilization failure or low fertilization ratein conventional IVF-ET cyclesObjective: To find the clinical factors relating with fertilization failure orlow fertilization rate conventional in vitro fertilization(IVF) cycles. Methods: The clinical information of cycles undergoing IVF-ET in theART Department of the Second Hospital of Hebei Medical University fromMarch2009to November2011was retrospectively analyzed. They weredivided into three groups according to the rate of fertilization situation: totalfertilization failure group (group A), low fertilization rate group (fertilizationrate <30%)(group B), normal fertilization rate group (group C). The RescueICSI and Half-ICSI cycles were divided respectively into group A, group Band group C according to the fertilization rate. It was eventually a total of51cycles of group A,82cycles of group B, a total of1857cycles of group C.Compare the following content among the three groups:①The female age,duration of infertility, rate of the infertility factors, basic follicle-stimulationhormone (bFSH) level, basic luteotropic hormone (bLH) level, basicestradiol(bE2) level;②ovarian stimulation protocol, Gn consumption, durationof Gn, the hormone level at hCG injection day, Per eggs E2level at hCGinjection day,③average number of obtained oocytes, the rate of matureoocytes, the rate of abnormal oocytes, the normal fertilization rate;④spermdensity, motility, the proportion of Grade A and progressive sperm before andafter optimal treatment, the proportion of sperm with abnormal morphology(＞85%)Results: In1990conventional IVF cycles, there were51cycles with totalfertilization failure (group A), accounting for2.56%of the total,82cycleswith fertilization rate <30%(group B), accounting for4.12%of the total,Group A included16cycles of Rescuel ICSI of and11cycles of Half-ICSI,with the total of27cycles. Group B included16cycles of Rescuel ICSI of and18cycles of Half-ICSI, with the total of34cycles. The cycles with thefertilization rate≥30%(group C) in the same period were matched as thecontrol (n=1857). The results of the comparison were as follows:①Thefemale age in the three groups were (31.88±3.81)years,(31.00±3.75)years,(31.26±4.25)years respectively, the average age of group A was higher thanthat of group B and group C, but failed to reach statistics difference; Theduration of infertility of the group A, B and C were (5.44±2.35)years, (4.85±2.43)years,(4.60±2.50)years respectively, the duration of group A andgroup B were both longer than that of group C(P<0.05); The rates of primaryinfertility of the three groups were64.7%,63.4%,47.8%respectively, the rateof group A and group B were both higher than that of group C(χ~2=5.705,P<0.05; χ~2=7.701, P<0.05); The rate of tubal infertility, male infertility andunexplained infertility of the three groups were respectively36.4%,28.8%,15.2%,40.0%,30.9%,8.2%,68.7%,11.0%,0.7%. There was no significantdifference in the above three factors between the group A and B, however therate of tubal infertility of groups A and B were both lower than that of groupC(χ~2=30.497, P<0.05; χ~2=38.942, P<0.05). On the contrary the rate of maleinfertility of groups A and B were both higher than that of group C(χ~2=19.777,P<0.05; χ~2=39.134, P<0.05); and the rate of unexplained infertility of group Aand B were both higher than that of group C (χ~2=115.149, P<0.05; χ~2=53.377,P<0.05). There were no significant differences in the terms of bFSH level,bLH level, and bE2level among the three groups.②The rate of ovarianstimulation protocol, Gn consumption, duration of Gn, the LH, E2, P, Per eggsE2level at hCG injection day were all similar among the three groups.③Thenumber of average oocytes in group A, B and C were10.7±8.5,14.0±7.9,12.1±7.5respectively. The number of group B was higher than that of groupC(P<0.05).The rate of retrieval oocytes between1～4of the three groups were25.5%,9.8%,14.6%respectively. The rate of group A was higher than that ofthe other two groups(χ~2=5.854,P<0.05;χ~2=4.772,P<0.05); The rate of retrievaloocytes more than15in group B and group C were both higher than that ofgroup A, but failed to reach statistics differences; The rates of mature oocytesof the three groups were45.9%,61.0%,88.9%respectively, with thecomparation among the three groups all reaching statistics differences(P<0.05);The rate of abnormal oocytes of the three groups were15.9%,8.7%,0.4%,with the comparation among the three groups all reaching statistics differences(P<0.05); The normal fertilization rate in groups B was significantly lowerthan groups C (68.6%vs75.5%,χ~2=877.7,P<0.05).④The rate of using thedensity gradient centrifugation of the three groups was41.2%,28.9%,21.6% respectively, the rate of group A was significantly higer than group B and C(P<0.05).The sperm density before separation of group A, B and C were(38.53±15.87)×106/ml,(39.37±17.88)×106/ml,(45.80±18.92)×106/mlrespectively. The sperm density of group A and B were both lower than groupC(P<0.05); The sperm motility before separation in group A, B and C were(39.08±13.54)%,(43.84±13.87)%,(43.84±11.97)%respectively. The index ofgroup A were lower than that of group B and C(P<0.05); The rate of Grade Abefore separation of the three groups were (12.96±5.60)%,(14.70±6.23)%,(16.41±6.49)%repectively. The index of group A were lower than that ofgroup B and C (P<0.05); The rate of PMS before separation in group A, B andC were (27.18±9.26)%,(30.66±9.05)%,(31.39±9.16)%repectively. The indexof group A were lower than that of group B and C(P<0.05; P<0.05); Therewas no significant difference in the sperm density and sperm motility afterseparation among the three groups. The rate of Grade a after separation ingroup A, B and C were (46.06±12.53)%,(47.83±9.57)%,(50.63%±8.91)%repectively. There was no significant difference between group A and B, butboth of them were lower than that of groups C (P<0.05). Similarly the rate ofPMS after separation in the group A, B and C were (86.25±9.80)%,(87.62±6.68)%,(89.11±4.78)%repectively. There was no significantdifference between group A and B, but both of them were lower than that ofgroup C (P<0.05); The rate of abnormal morphology of sperm(>85%) ingroup A, B and C were19.6%,18.3%,10.8%repectively. There was nosignificant difference between group A and B, but both were higher thangroups C(χ~2=4.426,P<0.05;χ~2=3.894,P<0.05).Conclusion: Those patients with primary infertility, long infertilityduration, the unexplained infertility and male factor infertility have a high riskof total fertilization failure or low fertilization rate. Fertilization failure may beassociated with the inadequate of oocyte number, maturity, and low semenparameters or poor sperm quality. Part ⅡUse of Early rescue intracytoplasmic sperm injection andSubsequent intracytoplasmic sperm injection in patients withprevious fertilization failure or low fertilization rateafter conventional IVFObjective: To evaluate the clinical outcomes of the combination ofshort-period fertilization with early rescue intracytoplasmic sperminjection(R-ICSI) in patients after complete fertilization failure and lowfertilization rate in conventional in vitro fertilization(IVF) procedures and toanalyze the clinical outcomes of ICSI in patients with previous fertilizationfailure or low fertilization rate after conventional IVF.Methods: A retrospective study was carried out from the center ofReproductive Medicine of the second hospital of Hebei Medical Universityfrom January2011to December2011, including47cycles of early rescueintracytoplasmic sperm injection(R-ICSI)(Group A)with completefertilization failure and low fertilization rate after the combination ofshort-period fertilization in conventional in vitro fertilization(IVF) procedures,60cycles of conventional IVF and ICSI in one cycle(half-ICSI)(GroupB)with higher fertilization failure factors and more than eight occytesretrieved,31ICSI cycles(Group C) following a previous fertilization failureand low fertilization rate in conventional IVF, and425frist and direct ICSIcycles using ejaculated spermatozoa(group D) at the same period wereperformed. The clinical outcomes and laboratory parameters were comparedin Group A, B, D and in Group C, D were analyzed, including age, time ofinfertility, amount and time of gonadotropin administered, peak estradiollevels, number of oocytes retrieved, number of embryo transferred, percentageof diploid and triploidy zygotes, percentage of embryos can be utilized,percentage of embryo frozen cycles and implantation rates, pregnancy rates, abortion rates and something else.Results: Among the Group A, B and D, the age, time of infertility,amount and time of gonadotropin administered, percentage of triploidyzygotes, number of embryo transferred, percentage of embryo frozen cyclesand abortion rates showed no significant differences. The peak estradiol levels,number of oocytes retrieved, implantation rates and pregnancy rates in groupA showed significant differences from those in group B[(2236.14±1181.73)pg/ml vs (3211.46±1034.71) pg/ml,(11.60±7.17) vs (17.73±8.74),(17.02%vs32.41%) and (25.00%vs46.15%), respectively, P<0.05]. The percentage ofdiploid zygotes, percentage of embryo frozen cycles, implantation rates andpregnancy rates in group A were significantly lower than those in groupD[(72.49%vs88.50%),(36.36%vs53.03%),(17.02%vs33.03%) and(25.00%vs48.28%), respectively, P<0.05]. The peak estradiol levels, numberof oocytes retrieved, percentage of diploid zygotes and percentage of embryoscan be utilized in group B showed significant differences from those in groupD[(3211.46±1034.71)pg/ml vs (2618.43±1296.13)pg/ml,(17.73±8.74vs12.88±7.72),(74.97%vs88.50%) and (32.33%vs40.31%), respectively,P<0.05]. The age, number of oocytes retrieved, number of embryo transferred,percentage of embryo frozen cycles and implantation rates in group C showedsignificant differences from those in group D[(31.03±3.84)yesrs vs(29.04±4.49)yesrs,(9.35±6.23)vs(12.88±7.72),(2.55±0.73)vs (2.04±0.41),(32.26%vs53.03%) and (13.92%vs33.03%), respectively, P<0.05]. The timeof infertility, abortion rates in group C were higher than those of groupD[(5.57±3.73)years vs (4.46±3.30)yesrs and (20.00%vs13.11%)], and thepercentage of diploid zygotes, pregnancy rates were lower than those of groupD[(86.89%vs88.50%) and (32.26%vs48.28%)], but there were nosignificant differences.Conclusions: The combination of short-period fertilization with earlyR-ICSI can find and rescue complete fertilization failure and low fertilizationrate in conventional IVF procedures timely and get better clinical effect．Toimprove the clinical outcome of the patient with complete fertilization failure and low fertilization rate in conventional IVF, short-period fertilization withearly R-ICSI could be the first choice, while half ICSI can be applied in theinfertility patients with higher fertilization failure factors and more than eightoccytes retrieved. For patients who have previous complete fertilization failureor low fertilization rate after conventional IVF,ICSI may be a good choice toovercome previous fertilization failure, to improve fertilization rate andclinical outcomes of a second cycle. But for patients who have previouscomplete fertilization failure or low fertilization rate after conventional IVF,the implantation rate of ICSI embryos is lower. It suggests fertilization failureor low fertilization rate may be due at least partly to occyte abnormity, whichresults in the descent of embryo development potential.