The Cystic Anechoic Zone Of Uterine Cavity Newly Observed During Controlled Ovarian Hyperstimulation Affects Pregnancy Outcomes Of Fresh Embryo Transfer

BackgroundIn recent years,more and more studies have focused on the effect of intrauterine lesions on pregnancy outcomes during controlled ovarian hyperstimulation(COH).After entering the cycle,cystic anechoic zones can be seen in the uterine cavity during COH,which has a cystic structure.The sonographic features of it are as follows:one or more anechoic zones detected in the uterine cavity closing to the endometrium,poor internal penetration,and no blood flow signal around the anechoic zone shown by color Doppler flow imaging(CDFI).These cystic anechoic zones can be divided into regular and irregular cystic zones,which may be the ultrasonographic manifestations of local fluid in the uterine cavity or endometrial cyst.The fluid accumulation in cystic anechoic zones is different from that in endometrial cavity fluid and cesarean section scar diverticulum.What is the impact of this cystic anechoic zone newly observed during COH on the outcome of ET?Should the patients with this ultrasound manifestation continue to undergo the current cycle of ET,or cancel the current cycle and switch to frozen embryo transfer?At present,there is no unified treatment plan for this in clinic.Therefore,it is of guiding significance for the treatment of patients to explore the cause of uterine cystic anechoic zone and whether it will affect the pregnancy outcomes.Objective1.To explore the effect of newly observed uterine cystic anechoic zone on the pregnancy outcomes of fresh ET during COH.2.To study the effect of uterine cystic anechoic zone on the type of endometrium.3.To analyze whether the diameter of uterine cystic anechoic zone affects the outcome of pregnancy.MethodsTo collect the information of patients who received in vitro fertilization/intracytoplasmic sperm injection(IVF/ICSI)and received fresh ET in the Hospital for Reproductive Medicine Affiliated to Shandong University from January 2014 to December 2020.Propensity score matching(PSM)was used to match the proportion of infertile patients with cystic anechoic zones and non-cystic anechoic zones at 1:2 ratio.Live birth is the main outcome.Other outcomes mainly included biochemical pregnancy,clinical pregnancy and pregnancy loss(miscarriage during biochemical pregnancies and clinical pregnancies).The robust error variance estimation method,Modified poisson regression,was used to analyze the matched data,and the relative risk(RR)and 95%confidence interval(CI)before and after adjusting the confounding factors were calculated.Correlation analysis was used to explore the relationship between the diameter of uterine cystic anechoic zone and pregnancy outcomes,and the correlation coefficient(r)was provided.ResultAccording to the inclusion and exclusion criteria,a total of 31523 patients were included,including cystic anechoic zone group(n=182)and non-cystic anechoic zone group(n=31341).After PSM,179 patients were included in the cystic anechoic zone group and 358 patients in the non-cystic anechoic zone group.1.The live birth rate(38.0%vs 48.6%,P=0.025)of patients with uterine cystic anechoic zones was lower than that in the non-uterine cystic anechoic zone group,while for clinical pregnancy miscarriage rate(22.2%vs 12.4%,P=0.031),the rate was higher.When adjusting for potential confounders,there were some differences in the rate of live birth[adjusted RR,0.788(95%CI,0.638-0.974;P=0.027)]and clinical pregnancy miscarriage[adjusted RR,0.557(95%CI,0.325-0.953;P=0.033)]between patients with and without uterine cystic anechoic zones.2.There was a significant difference in the endometrium patterns between the two groups(P<0.001).In the cystic anechoic zone group,the proportion of type B endometrium was higher than that of type A endometrium,while the control group was on the contrary.3.The results showed no correlation in the association between live birth rate(r=-0.027,P=0.718),clinical pregnancy rate(r=-0.037,P=0.620)and biochemical pregnancy rate(r=-0.015,P=0.840)and the diameters of the cystic anechoic zones in the uterine cavity.Conclusion1.The presence of cystic anechoic zones of the uterine cavity during COH significantly reduced the live birth rate and increased the clinical miscarriage rate.2.The diameter of uterine cystic anechoic zone does not affect the outcome of pregnancy.3.The cystic anechoic zone of the uterine cavity may affect the type of endometrium.