Epidemiological Survey and Risk Factor Analysis of Recurrent Spontaneous Miscarriages in Infertile Women at Large Infertility Centers

Background：A higher frequency of spontaneous miscarriage has been observed in infertile couples,and there is a higher prevalence of infertility among patients with a history of recurrent spontaneous miscarriages （RSMs;〉2 miscarriages）.This study aimed to determine the proportion of infertile patients with RSM and examine risk factors associated in patients with RSM being treated with assisted reproductive technologies.Methods：This cross-sectional observational study was conducted at six reproductive medicine centers in three cities of China.Data of 751 patients with at least one spontaneous miscarriage were analyzed.Demographic data and etiological factors associated with infertility were compiled and compared between patients with a single spontaneous miscarriage （SSM） and those with RSM.Results：Two hundred （26.6%,95% confidence interval [CI]：23.50-29.95%） patients experienced RSMs and 551 （73.4%） had a single miscarriage.The odds of RSM increased with increasing age （odds ratio [OR] =1.06）,uterine disorders （OR =2.09）,endocrine disorders （OR =2.48）,and immune disorders （OR =2.98）.Higher education level,masters or above,and a pelvic cavity disorder were associated with lower risk of RSM （OR =0.27 and 0.46,respectively）.Late spontaneous miscarriages were more frequent in patients with RSM than in those with a SSM （31.5% vs.14.2%,respectively,P 〈 0.001） and were associated with a history of uterine cavity procedures （OR =2.095） and cervical factors related to infertility （OR =4.136,95% CI：1.012-16.90）.Conclusions：Compared to patients with only a SSM,the conditions of patients with RSM are more complicated.To increase the success rate of assisted reproductive technology,factors including uterus cavity adhesion,cervical relaxation,endocrine disorders,and immune disorders should be treated before assisted reproduction is initiated.These data may provide treatment guidance for infertile patients with a history of RSM.

Analysis of factors related to early miscarriage after in vitro fertilization embryo transfer

Aims:This research aims to explore the factors related to early spontaneous miscarriage after in vitro fertilization and embryo transfer(IVF-ET)pregnancy,and to provide guidance for improving pregnancy outcomes.Methods:We retrospectively analyzed the data for clinical pregnant women(2591 cycles)undergoing IVF-ET at the reproductive center of Peking University People’s Hospital from January 2017 to December 2018;This included 544 ET cycles and 2047 frozen embryo transfer cycles.The analysis of factors associated with early miscarriage in the overall population of IVF/intracytoplasmic sperm injection(ICSI)pregnancies(including fresh and thawing cycles)was performed.Results:The risk of early miscarriage in the 35–39 age group was 1.35 times higher than that in the<35 age group(OR=1.35[1.05,1.73],p=0.02).In addition,the risk of early miscarriage was 3.88 times higher in the group40 years old than in the group<35 years old(OR=3.88[2.68,5.62],p<0.001).Endometrial thickness also affected the miscarriage rate;the early miscarriage risk with endometrial thickness8.5 mm was 0.78 times than that of the<8.5 mm group(OR=0.78[0.62,0.98],p=0.03).The early miscarriage rate during frozen embryo transfer was 1.48 times higher than that during fresh embryo transfer(OR=1.48[1.08,2.02],p=0.01),while in the fresh cycle,the risk of early miscarriage with high-quality embryos was 0.5 times lower than that with nonhigh quality embryos(OR=0.5[0.27,0.9],p=0.02).In the frozen cycle,the risk of early miscarriage in natural cycle transplantation was 0.73 times that in hormone replacement treatment(HRT)cycle transplantation(OR=0.73[0.54,0.97],p=0.03).Conclusions:Advanced age is an independent risk factor for early miscarriage,while endometrial thickness at the date of transplantation is an independent protective factor.The risk of early miscarriage in fresh-cycle transplanted embryos is significantly lower than that in frozen embryos,and the number of high-quality embryos in the fresh cycle lowers the miscarriage rate significantly.Natural cycle transplantation has a lower rate of early miscarriage than hormone replacement therapy.