ObjectiveTo explore the occurrence， in vitro culture effect and clinical outcomes of embryo contamination during in vitro fertilization and embryo transfer （IVF-ET） cycles. MethodsA retrospective analysis was made on the embryo contamination cases during IVF-ET treatment at Reproductive Medicine Centre， Department of Obstetrics and Gynecology， Sun Yat-sen Memorial Hospital， Sun Yat-sen University from January 2010 to December 2020. We compared the contamination of 4 different insemination methods， contamination on 3 different in vitro culture days （D1， D2， D3） and contamination of 3 different samples （follicular fluid， semen and culture medium）. The source of contamination and types of microbes were identified. We also compared in vitro culture and clinical outcomes between two groups （42 cases of all embryos contaminated and 28 cases of partial embryos contaminated）. ResultsAmong the 29 583 cycles examined， 70 cycles had microbial contamination （0.24%）， and all contaminated embryos were from in vitro fertilization （IVF） source rather than intracytoplasmic sperm injection （ICSI） source. The contamination rate on D2 was the highest （54.3%）， followed by those on D1 （32.9%） and D3 （12.9%）. Compared with follicular fluid， semen is the most common source of contamination from D1-D3. The most common contaminants identified was Enterococcus faecalis in follicular fluid （18.0%）， while it was Escherichia coli in semen （59.6%） and culture medium （66.7%）. Moreover， the types of bacteria in culture medium were not consistent with those in follicular fluid and semen in 5 cases of microbial contamination. Compared with the Total contaminated group， the Partial contaminated group showed a significant decrease in No available embryo rates （6/28 vs. 34/42， 21.4% vs. 81.0%， P<0.001） and a rising trend in formation of blastocyst rates （5/12 vs. 2/7， 41.2% vs. 28.6%， P=0.656）， meanwhile， the clinical pregnancy cases and live births cases after transplantation of fresh and frozen-thawed cycles in Partial contaminated group were higher than those in the Total contaminated group. ConclusionICSI can effectively reduce embryo contamination. Embryo contamination mainly occurred on D2 in vitro culture and the most common contamination source is Escherichia coli in semen. Partial embryo contamination may still result in good in vitro culture effect and clinical outcomes during IVF-ET cycles.

Objective To investigate the impacts of body mass index (BMI) and age on in vitro fertilization-embryo transfer (IVF) and intracytoplasmic sperm injection (ICSI) treatment in infertile patients without polycystic ovary syndrome (PCOS). Methods A retrospective study of 1426 patients during Jun. 2001 - Nov. 2009 was carried out. Multiple regression was used to analyze the effects of BMI (low weight: BMI＜18.5 kg/m2, normal weight:BMI 18.5-23.99 kg/m2 and over weight-obesity: BMI≥24 kg/m2) and age (young: 20-34 years old, eld: 35-45 years old) on controlled ovarian stimulation (COH)[including:dose and duration of Gn, E2 level on day of human chorionic gonadotropin (HCG) administration, number of oocytes collected and full-grown follicles ],number of fertilization, cleavage, two-pronucleus, normal embryos and cryopreserved embryos and clinical pregnancy outcome. Results ( 1 ) Gn dose for the patients whose age were 35 and the above,had a positive correlation with age (P＜0.001), 12.70% of the total variation of Gn dose was related to age (standardized partial regression coefficient was 0.343). (2) Estradiol level on day of HCG administration had a negative correlation with BMI in overweight-obesity patients, and so were the patients whose age were 35 and above (P value respectively lower than 0.037 and 0.018). 0.80% of the total variation of estradiol (HCG day) is related to age and overweight-obesity while age took greater proportion (standardized partial regression coefficients were 0.066 and 0.058 respectively). (3)For older patients, age appeared to have negative relationships with duration of Gn and number of oocytes collected, full-grown follicles, fertilization, cleavage, two-pronucleus, normal embryos and cryopreserved embryos (P＜0.05). (4)Compared to young-normal weight patients, the odds ratio of pregnancy in eld-low weight and eld-overweight-obesity patients were 0.482 and 0.529 (P＜0.05)respectively. Conclusion Age, but not the BMI, had significant effects on IVF/ICSI treatment. It seems that factors as losing weight before IVF or ICSI treatment effective in reducing the dose of Gn.