Background: This study aimed to investigate the obstetric and perinatal outcomes of singleton deliveries following frozen embryo transfer (FET) cycles using different endometrial preparation methods. Methods: We analyzed data on 44,118 singleton pregnant women who underwent in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI), resulting in delivery or abortion, from the South Korean National Health Insurance Service database. Stratification was based on the type of embryo transfer, viz. fresh embryo transfer and FET cycles, using International Classification of Diseases (Tenth Revision) diagnostic codes, national procedural codes, and prescription medication data within the IVF/ICSI pregnancy cohort. FET was subcategorized into artificial cycle-FET (AC-FET), natural cycle-FET (NC-FET), and stimulated cycle-FET (SC-FET) for comparative analyses of the pregnancy, obstetric, and perinatal outcomes. Results: AC-FET was associated with higher risks of hypertensive disorders of pregnancy, preeclampsia, placenta accreta, and postpartum hemorrhage compared with NC-FET; the risk of macrosomia showed no significant differences. SC-FET was associated with a lower risk of miscarriage and higher rate of term birth beyond 37 weeks compared with NCFET. However, SC-FET was associated with elevated risks of gestational hypertension and postpartum hemorrhage when compared to NC-FET. Conclusion The rate of adverse obstetric and perinatal outcomes was higher in AC-FET compared to NC-FET, highlighting NC-FET as a valuable option owing to better maternal and fetal safety. In cases where NC-FET is not feasible, SC-FET presented as a favorable alternative, exhibiting lower miscarriage rates than NC-FET and better obstetric outcomes than AC-FET.

Background: This study aimed to investigate the obstetric and perinatal outcomes of singleton deliveries following frozen embryo transfer (FET) cycles using different endometrial preparation methods. Methods: We analyzed data on 44,118 singleton pregnant women who underwent in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI), resulting in delivery or abortion, from the South Korean National Health Insurance Service database. Stratification was based on the type of embryo transfer, viz. fresh embryo transfer and FET cycles, using International Classification of Diseases (Tenth Revision) diagnostic codes, national procedural codes, and prescription medication data within the IVF/ICSI pregnancy cohort. FET was subcategorized into artificial cycle-FET (AC-FET), natural cycle-FET (NC-FET), and stimulated cycle-FET (SC-FET) for comparative analyses of the pregnancy, obstetric, and perinatal outcomes. Results: AC-FET was associated with higher risks of hypertensive disorders of pregnancy, preeclampsia, placenta accreta, and postpartum hemorrhage compared with NC-FET; the risk of macrosomia showed no significant differences. SC-FET was associated with a lower risk of miscarriage and higher rate of term birth beyond 37 weeks compared with NCFET. However, SC-FET was associated with elevated risks of gestational hypertension and postpartum hemorrhage when compared to NC-FET. Conclusion The rate of adverse obstetric and perinatal outcomes was higher in AC-FET compared to NC-FET, highlighting NC-FET as a valuable option owing to better maternal and fetal safety. In cases where NC-FET is not feasible, SC-FET presented as a favorable alternative, exhibiting lower miscarriage rates than NC-FET and better obstetric outcomes than AC-FET.

Background: This study aimed to investigate the obstetric and perinatal outcomes of singleton deliveries following frozen embryo transfer (FET) cycles using different endometrial preparation methods. Methods: We analyzed data on 44,118 singleton pregnant women who underwent in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI), resulting in delivery or abortion, from the South Korean National Health Insurance Service database. Stratification was based on the type of embryo transfer, viz. fresh embryo transfer and FET cycles, using International Classification of Diseases (Tenth Revision) diagnostic codes, national procedural codes, and prescription medication data within the IVF/ICSI pregnancy cohort. FET was subcategorized into artificial cycle-FET (AC-FET), natural cycle-FET (NC-FET), and stimulated cycle-FET (SC-FET) for comparative analyses of the pregnancy, obstetric, and perinatal outcomes. Results: AC-FET was associated with higher risks of hypertensive disorders of pregnancy, preeclampsia, placenta accreta, and postpartum hemorrhage compared with NC-FET; the risk of macrosomia showed no significant differences. SC-FET was associated with a lower risk of miscarriage and higher rate of term birth beyond 37 weeks compared with NCFET. However, SC-FET was associated with elevated risks of gestational hypertension and postpartum hemorrhage when compared to NC-FET. Conclusion The rate of adverse obstetric and perinatal outcomes was higher in AC-FET compared to NC-FET, highlighting NC-FET as a valuable option owing to better maternal and fetal safety. In cases where NC-FET is not feasible, SC-FET presented as a favorable alternative, exhibiting lower miscarriage rates than NC-FET and better obstetric outcomes than AC-FET.

Background: This study aimed to investigate the obstetric and perinatal outcomes of singleton deliveries following frozen embryo transfer (FET) cycles using different endometrial preparation methods. Methods: We analyzed data on 44,118 singleton pregnant women who underwent in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI), resulting in delivery or abortion, from the South Korean National Health Insurance Service database. Stratification was based on the type of embryo transfer, viz. fresh embryo transfer and FET cycles, using International Classification of Diseases (Tenth Revision) diagnostic codes, national procedural codes, and prescription medication data within the IVF/ICSI pregnancy cohort. FET was subcategorized into artificial cycle-FET (AC-FET), natural cycle-FET (NC-FET), and stimulated cycle-FET (SC-FET) for comparative analyses of the pregnancy, obstetric, and perinatal outcomes. Results: AC-FET was associated with higher risks of hypertensive disorders of pregnancy, preeclampsia, placenta accreta, and postpartum hemorrhage compared with NC-FET; the risk of macrosomia showed no significant differences. SC-FET was associated with a lower risk of miscarriage and higher rate of term birth beyond 37 weeks compared with NCFET. However, SC-FET was associated with elevated risks of gestational hypertension and postpartum hemorrhage when compared to NC-FET. Conclusion The rate of adverse obstetric and perinatal outcomes was higher in AC-FET compared to NC-FET, highlighting NC-FET as a valuable option owing to better maternal and fetal safety. In cases where NC-FET is not feasible, SC-FET presented as a favorable alternative, exhibiting lower miscarriage rates than NC-FET and better obstetric outcomes than AC-FET.

Purpose: To investigate urine microbiome differences among healthy women, women with recurrent uncomplicated cystitis (rUC), and those with sporadic/single uncomplicated cystitis (sUC) to challenge traditional beliefs about origins of these infections. Materials and Methods: Patients who underwent both conventional urine culture and next-generation sequencing (NGS) of urine were retrospectively reviewed. Symptom-free women with normal urinalysis results as a control group were also studied. Samples were collected via transurethral catheterization. Results: In the control group, urine microbiome was detected on NGS in 83.3%, with Lactobacillus and Prevotella being the most abundant genera. The sensitivity of urine NGS was significantly higher than that of conventional urine culture in both the sUC group (91.2% vs. 32.4%) and the rUC group (82.4% vs. 16.4%). In urine NGS results, Enterobacterales, Prevotella, and Escherichia/ Shigella were additionally found in the sUC group, while the recurrent urinary tract infection (rUTI)/rUC group exhibited the presence of Lactobacillus, Prevotella, Enterobacterales, Escherichia/Shigella, and Propionibacterium. Moreover, distinct patterns of urine NGS were observed based on menopausal status and ingestion of antibiotics or probiotics prior to NGS test sampling. Conclusions Urine microbiomes in control, sUC, and rUTI/rUC groups exhibited distinct characteristics. Notably, sUC and rUC might represent entirely separate pathological processes, given their distinct urine microbiomes. Consequently, the use of urine NGS might be essential to enhancing sensitivity compared to conventional urine culture in both sUC and rUTI/rUC groups.