Relationship between maternal mortality and ritodrine hydrochloride as a tocolytic agent in Japan.

AIM: In Japan, unlike Western countries, tocolytic agents are administered in long-term protocols to treat threatened preterm labor. Evaluating the side effects of this practice is crucial. We examined whether ritodrine hydrochloride had been administered in cases of maternal death, aiming to investigate any relationship between ritodrine administration and maternal death. METHODS: This retrospective cohort study used reports of maternal deaths from multiple institutions in Japan between 2010 and 2020. Data on the reported cases were retrospectively analyzed, and data on the route of administration, administered dose, and clinical findings, including causes of maternal death, were extracted. The amount of tocolytic agents was compared between maternal deaths with ritodrine administration and those without. RESULTS: A total of 390 maternal deaths were reported to the Maternal Death Exploratory Committee in Japan during the study period. Ritodrine hydrochloride was administered in 32 of these cases. The frequencies (n) and median doses (range) of oral or intravenous ritodrine hydrochloride were 34.4% (11) and 945 (5-2100) mg and 84.4% (27) and 4032 (50-18 680) mg, respectively. Frequencies of perinatal cardiomyopathy, cerebral hemorrhage, diabetic ketoacidosis, and pulmonary edema as causes of maternal death were significantly higher with ritodrine administration than without it. CONCLUSIONS: Our results suggest a relationship between long-term administration of ritodrine hydrochloride and an increased risk of maternal death due to perinatal cardiomyopathy, cerebral hemorrhage, diabetic ketoacidosis, and pulmonary edema. In cases where ritodrine should be administered to prevent preterm labor, careful management and monitoring of maternal symptoms are required.

The development of early human lymphatic vessels as characterized by lymphatic endothelial markers.

Lymphatic vessel development studies in mice and zebrafish models have demonstrated that lymphatic endothelial cells (LECs) predominantly differentiate from venous endothelial cells via the expression of the transcription factor Prox1. However, LECs can also be generated from undifferentiated mesoderm, suggesting potential diversity in their precursor cell origins depending on the organ or anatomical location. Despite these advances, recapitulating human lymphatic malformations in animal models has been difficult, and considering lymphatic vasculature function varies widely between species, analysis of development directly in humans is needed. Here, we examined early lymphatic development in humans by analyzing the histology of 31 embryos and three 9-week-old fetuses. We found that human embryonic cardinal veins, which converged to form initial lymph sacs, produce Prox1-expressing LECs. Furthermore, we describe the lymphatic vessel development in various organs and observe organ-specific differences. These characterizations of the early development of human lymphatic vessels should help to better understand the evolution and phylogenetic relationships of lymphatic systems, and their roles in human disease.

The efficacy of vaginal treatment for non-Lactobacillus dominant endometrial microbiota-A case-control study.

AIM: Reduced Lactobacillus occupancy in the uterine microflora has been associated with implantation failure. This study aimed to evaluate a treatment for improving the uterine microflora. METHODS: This study included patients diagnosed with repeated implantation failure-defined as failure to achieve pregnancy after two or more transfers of viable embryos-who were classified as non-Lactobacillus dominant. Treatment A comprised oral administration of antibiotics for 1 week, followed by oral probiotic butyrate tablets (3 g/day) for approximately 30 days. Treatment B comprised a 1-week course of oral (750 mg/day) and vaginal (250 mg/day) metronidazole, followed by a 1-week intravaginal administration of probiotic capsules (1 capsule/day) and continued oral administration of probiotics (1 capsule/day). Both treatments were compared in terms of efficacy in improving vaginal flora. Improvement was defined as Lactobacillus occupancy >90% or an increase in Lactobacillus occupancy >20%. RESULTS: Seven (41.2%) of 17 patients in the Treatment A group improved in response to the treatment. Contrastingly, 9 (90.0%) of 10 patients improved in the Treatment B group (p = 0.0127). Following treatment, Lactobacillus occupancy in the Treatment B group (62.9% ± 12.7%) was significantly higher than that in the Treatment A group (5.7% ± 9.8%) (p = 0.0242). CONCLUSIONS: This study demonstrates the effectiveness of combining antibiotics and probiotics in vaginal formulations for treating abnormal uterine microflora. However, its potential impact on in vitro fertilization outcomes remains unclear and warrants further investigation through larger, more comprehensive studies.

Visceral Adipose Tissue Percentage Compared to Body Mass Index as Better Indicator of Surgical Outcomes in Women with Obesity and Endometrial Cancer.

STUDY OBJECTIVE: To assess the impact visceral adipose tissue percentage (VAT%) on surgical outcomes during minimally invasive surgery in obese women with endometrial cancer. DESIGN: Retrospective observational cohort study. SETTING: Mie University Hospital, Japan. PATIENTS: Of the 73 women (body mass index [BMI] >30 kg/m2) with obesity and primary endometrial cancer, 52 underwent robotic surgery, while 21 underwent laparoscopic surgery between April 2014 and December 2022. INTERVENTIONS: We investigated the correlation between surgical outcomes (operative time and blood loss) and obesity (BMI and visceral adipose tissue percentage [VAT%]). MEASUREMENTS AND MAIN RESULTS: Abdominal fat-related parameters were measured at the level of the umbilicus using preoperative computed tomography. A weak negative correlation was found between BMI and VAT% (CC = -0.313, p = .001). Multivariate analysis showed that VAT% had a stronger correlation to total and practical operative time than BMI (ß = 0.338 vs 0.267, ß = 0.311 vs 0.209, respectively) and was an independent predictor of blood loss. VAT% was an independent predictive marker prolonged for operative time and increased blood loss during lymphadenectomy. CONCLUSION: VAT% could be an indicator of surgical outcomes for patients with obesity and endometrial cancer.

Management of pulmonary hemodynamics prior to delivery in a pregnant woman with development of decompensated pulmonary arterial hypertension.

Prompt termination of pregnancy in patients with decompensated pulmonary arterial hypertension (PAH) is imperative for improvement of maternal hemodynamics, but such termination may also result in maternal death due to further deterioration of PAH immediately after delivery. However, there have been limited reports on whether implementation of PAH therapy with continuation of pregnancy improves the maternal outcome, especially in treatment-naïve patients with PAH. A 24-year-old woman was admitted to our hospital with a chief complaint of dyspnea (WHO functional class IV) at 22 weeks and 3 days of gestation. She was diagnosed with PAH accompanied by right heart failure and low cardiac output. Intensive treatment was initiated with inotropic agents, oxygen therapy, and PAH therapy, resulting in improvement of her hemodynamics. A caesarean section was performed at 23 weeks and 3 days. Although her pulmonary arterial pressure transiently increased with oxygenation deteriorating immediately after delivery, worsening PAH improved without mechanical circulatory support. She continued receiving pulmonary vasodilators without relapse of pulmonary hypertension for three years. The improvement of pulmonary hemodynamics prior to delivery with PAH therapy led to a favorable outcome after delivery. Learning objective: Pulmonary hemodynamics in pregnant patients with pulmonary arterial hypertension (PAH) can deteriorate with the continuation of pregnancy, while termination can also cause PAH surge immediately after delivery. In treatment-naïve patients with PAH, who are most likely to benefit from PAH therapy, implementation of PAH therapy with continuation, even with a decompensated status, may improve the hemodynamics prior to delivery, resulting in a favorable outcome after delivery.

Investigation of optimal weight gain during pregnancy: A retrospective analysis of the Japanese perinatal registry database.

AIM: This study aimed to determine the weight gain during pregnancy that minimizes the predicted probability of various perinatal adverse events according to the pre-pregnancy body mass index (BMI) and make recommendations for optimal weight gain in Japan. METHODS: The Japan Society of Obstetrics and Gynecology perinatal database for 2015-2017 was used. From the 719 723 deliveries included in this database, parturients with underlying diseases or missing data were excluded, and 419 114 deliveries were analyzed. A questionnaire survey was also conducted to weigh each perinatal adverse event. For each of the nine outcomes, a restricted cubic spline model was made to estimate the association between the "expected gestational weight gain at 40 weeks" and the outcome risk. RESULTS: Since the classes of medical facilities were generally the same, weights were assigned according to the mean of the questionnaires rather than by the class of the facility. For each pre-pregnancy BMI, the weight gains during pregnancy that minimized the predicted probability of various adverse perinatal events were 12-15, 10-13, 7-10, and upper limit of 5 kg for the underweight, normal-weight, obese 1, and obese ≥2 groups, respectively. CONCLUSIONS: The weight gain during pregnancy that minimizes the predicted probability of various perinatal adverse events according to the pre-pregnancy BMI was established.

Safety and dose-finding trial of tadalafil administered for fetus in labor: A phase I clinical study.

AIM: This study aimed to investigate the safety and efficacy of tadalafil in protecting the fetus from hypoxic stress caused by repeated labor pains during delivery and preventing fetal hypoxic-ischemic encephalopathy. METHODS: The study used a three-case cohort approach. Three patients were administered 10 mg tadalafil and monitored for serious adverse events. In the absence of serious tadalafil-associated adverse events as assessed by the Safety Evaluation Committee, three new patients were added to the study and treated with 20 mg/dose. The blood levels of tadalafil were recorded before and after 2, 4, 8, and 12 h of administration and 2 h after delivery. RESULTS: A total of seven patients were enrolled, and after excluding one patient who delivered before 37 weeks, tadalafil was administered to six patients. Maternal adverse events were considered acceptable from the maternal perspective, with grade 1 headache, anorexia, and myalgia and no obstetrical complications after delivery at both doses. No serious neonatal adverse events were associated with tadalafil. Tadalafil blood levels remained stable at both doses. In addition, the level of soluble fms-like tyrosine kinase-1 did not alter, while that of the placental growth factor differed significantly before and after tadalafil administration. CONCLUSIONS: The study confirmed the safety of tadalafil administration during delivery for both mothers and newborns. The stable tadalafil blood levels confirmed the efficacy of the tested administration regime at 12 h interval. These findings would assist in conducting phase II trials to further verify the optimal dose and safety of tadalafil.

Breast Cancer Resistance Protein Limits Fetal Transfer of Tadalafil in Mice.

Tadalafil, a phosphodiesterase 5 (PDE5) inhibitor, is a candidate therapeutic agent for fetal growth restriction and hypertensive disorders of pregnancy. In this study, we elucidated the fetal transfer of tadalafil in comparison with that of sildenafil, the first PDE5 inhibitor to be approved. We also examined the contributions of multidrug resistance protein 1 (MDR1) and breast cancer resistance protein (BCRP) to fetal transfer. Tadalafil or sildenafil was administered to wild-type, Mdr1a/b-double-knockout or Bcrp-knockout pregnant mice by continuous infusion from gestational day (GD) 14.5 to 17.5, and the fetal-to-maternal plasma concentration ratio of unbound drug (unbound F/M ratio) was evaluated at GD 17.5. The values of unbound F/M ratio of tadalafil and sildenafil in wild-type mice were 0.80 and 1.6, respectively. The unbound F/M ratio of tadalafil was increased to 1.1 and 1.7 in Mdr1a/b-knockout and Bcrp-knockout mice, respectively, while the corresponding values for sildenafil were equal to or less than that in wild-type mice, respectively. A transcellular transport study revealed that basal-to-apical transport of both tadalafil and sildenafil was significantly higher than transport in the opposite direction in MDCKII-BCRP cells. Our research reveals that tadalafil is a newly identified substrate of human and mouse BCRP, and it appears that the fetal transfer of tadalafil is, at least in part, attributed to the involvement of BCRP within the placental processes in mice. The transfer of sildenafil to the fetus was not significantly constrained by BCRP, even though sildenafil was indeed a substantial substrate for BCRP.

Two-dimensional phase-contrast MRI reveals changes in uterine arterial blood flow in pregnant women administered tadalafil for fetal growth restriction.

INTRODUCTION: We aimed to examine the effect of uterine arterial (UtA) blood flow changes after tadalafil treatment for fetal growth restriction (FGR) using two-dimensional (2D) phase-contrast magnetic resonance imaging (PC-MRI). METHODS: We recruited 14 pregnant women with FGR aged 20-44 years, at ≥20 weeks' gestation, between May 2019 and July 2020. They underwent 2D PC-MRI for UtA blood flow measurement 3 days (interquartile range: 2-4) after diagnosis. This group (FGR group) was compared with 14 gestational age (GA)-matched healthy pregnant women (control group). Six patients in the FGR group received treatment with tadalafil administered at 20 mg twice daily after the first MRI until delivery. They underwent a second MRI a week later. RESULTS: The median total UtA blood/body surface area was 420 mL/min/m2 (290-494) in the FGR group and 547 mL/min/m2 (433-681) in the control group (p = 0.01). Percent increase in blood flow were significantly different between the FGR cases treated with tadalafil and control at 15.8 % (14.3-21.3) and 4.2 % (3.6-8.7), respectively (p = 0.03). DISCUSSION: UtA blood flow in pregnant women with FGR was significantly lower than that in healthy pregnant women. Tadalafil is expected to improve UtA blood flow, thereby improving placental function in pregnant patients with FGR.

Carboxylated Poly-L-lysine Potentially Reduces Human Sperm DNA Fragmentation after Freeze-Thawing, and Its Function Is Enhanced by Low-Dose Resveratrol.

Sperm DNA fragmentation (SDF) that occurs during the freezing-thawing of sperm may negatively impact the treatment outcomes of assisted reproductive technologies (ART). In a previous study, we developed a human sperm cryopreservation reagent containing carboxylated poly-L-lysine (CPLL) that reduced SDF after freeze-thawing compared with clinically popular cryopreservation reagents containing human serum albumin. However, it is unclear whether CPLL reduces SDF, as it differed from the constituents of the commercial cryopreservation reagents used for comparison. Therefore, here, we examined whether CPLL reduces the SDF of human sperm and evaluated reactive oxygen species (ROS) levels and lipid peroxidation (LPO), which are the causes of SDF; mitochondrial injury, ROS production; and impaired sperm motility. Furthermore, optimal antioxidants and their concentrations that could further enhance the reduction in SDF were determined for future clinical application in ART and underwent the same functional evaluations. CPLL can reduce SDF via inhibition of intracytoplasmic ROS and LPO. Furthermore, the addition of 0.1 mM resveratrol avoided the enhancement of SDF, which potentially affects mitochondrial and cytoplasmic ROS and LPO. This novel human sperm cryopreservation reagent containing CPLL and resveratrol has the potential to improve treatment outcomes in ART using frozen sperm.

Accurate evaluation of the progress of delivery with transperineal ultrasound may improve vaginal delivery: a single-center retrospective study.

Although digital examination of the cervix is the standard method used worldwide for evaluating the progress of delivery, it is subjective. Transperineal ultrasound (TPU) is combined with digital evaluation for accurate assessment of fetal descent and rotation of the advanced part of the fetus. This retrospective study aimed to clarify the impact of introducing TPU on perinatal outcomes at Mie University Hospital. We analyzed singleton pregnant women who underwent delivery management at our hospital between April 2020 and March 2021. Perinatal outcomes were compared between patients who used TPU (TPU+ group) and those who did not (TPU- group). The angle of progression and head direction were measured. The rate of vaginal delivery was significantly increased (90.9% vs. 71.6%; P = 0.0017), and the second stage of labor was significantly prolonged in the TPU+ group (148.1 vs. 75.8 min; P < 0.0001). A significant difference was observed in termination in the latent phase between the TPU+ group [3/8 (37.5%) cases] and TPU- group [20/25 (80.0%) cases] (P = 0.036). The rate of vaginal delivery can be increased through accurate evaluation of the progress of delivery with TPU.

Pregnancy Rates after Hysteroscopic Endometrial Polypectomy versus Endometrial Curettage Polypectomy: A Retrospective Study.

Background and Objectives: A relationship between endometrial polypectomy and in vitro fertilization (IVF) pregnancy outcomes has been reported; however, only a few studies have compared polyp removal techniques and pregnancy rates. We investigated whether different polypectomy techniques with endometrial curettage and hysteroscopic polypectomy for endometrial polyps affect subsequent pregnancy outcomes. Materials and Methods: Data from 434 patients who had undergone polypectomy for suspected endometrial polyps using transvaginal ultrasonography before embryo transfer in IVF at four institutions between January 2017 and December 2020 were retrospectively analyzed. Overall, there were 157 and 277 patients in the hysteroscopic (mean age: 35.0 years) and curettage (mean age: 37.3 years) groups, respectively. Single-blastocyst transfer cases were selected from both groups and age-matched to unify background factors. Results: In the single-blastocyst transfer cases, 148 (mean age: 35.0 years) and 196 (mean age: 35.9 years) were in the hysteroscopic and curettage groups, respectively, with the 148 cases matched by age. In these cases, the pregnancy rates for the first embryo transfer were 68.2% (odds ratio (OR): 2.14) and 51.4% (OR: 1.06) in the hysteroscopic and curettage groups, respectively; the resulting OR was 2.03. The pregnancy rates after up to the second transfer were 80.4% (OR: 4.10) and 68.2% (OR: 2.14) in the hysteroscopic and curettage groups, respectively, in which the OR was 1.91. The live birth rates were 66.2% (OR: 1.956) and 53.4% (OR: 1.15) in the hysteroscopic and curettage groups, respectively, in which the odds ratio was 1.71. These results show the effectiveness of hysteroscopic endometrial polypectomy compared to polypectomy with endometrial curettage. No significant difference was found regarding the miscarriage rates between the two groups. Conclusions: Hysteroscopic endometrial polypectomy resulted in a higher pregnancy rate in subsequent embryo transfer than polypectomy with endometrial curettage. Therefore, establishing a facility where polypectomy can be performed hysteroscopically is crucial.

Therapeutic Effect of Nicotinamide Mononucleotide for Hypoxic-Ischemic Brain Injury in Neonatal Mice.

SUMMARY STATEMENT: Neonatal hypoxia-ischemia reduces nicotinamide adenine dinucleotide (NAD+) and SIRT6 levels in the injured hippocampus.Hippocampal high mobility group box-1 (HMGB1) release is significantly increased after neonatal hypoxia-ischemia.Nicotinamide mononucleotide (NMN) treatment normalizes hippocampal NAD+ and SIRT6 levels, with significant decrease in caspase-3 activity and HMGB1 release.NMN improves early developmental behavior, as well as motor and memory function.

COVID-19 during pregnancy could potentially affect placental function.

OBJECTIVE: COVID-19 is an ongoing pandemic and has been extensively studied. However, the effects of COVID-19 during pregnancy, particularly on placental function, have not been verified. In this study, we used blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) to evaluate whether COVID-19 incidence during pregnancy has any lasting effects with respect to placental oxygenation. METHODS: This is a case-control study, in which eight cases of singleton pregnancies before 30 weeks gestation with COVID-19 mothers were included. Placental oxygenation was evaluated using BOLD-MRI after 32 weeks of gestation. BOLD-MRI was consecutively performed under normoxia (21% O2), hyperoxia (100% O2), and normoxia for 4 min each. Individual placental time-activity curves were evaluated to calculate the peak score (peakΔR2*) and the time from the start of maternal oxygen administration to the time of peakΔR2* (time to peakΔR2*). Eighteen COVID-19-free normal pregnancies from a previous study were used as the control group. RESULTS: No significant differences were found between the two groups regarding maternal background, number of days of delivery, birth weight, and placental weight. The parameter peakΔR2* was significantly decreased in the COVID-19 group (8 ± 3 vs. 5 ± 1, p < .001); however, there was no significant difference in time to peakΔR2* (458 ± 74 s vs. 471 ± 33 s, p = .644). CONCLUSIONS: In this study, BOLD-MRI was used to evaluate placental oxygenation during pregnancy in COVID-19-affected patients. COVID-19 during pregnancy decreased placental oxygenation even post-illness, but had no effect on fetal growth; further investigation of the possible effects of COVID-19 on the fetus and mother is warranted.

Tourniquet, Uterine Inversion, and Placental dissection （TURIP） procedure as a novel hemostatic technique to preserve fertility for placenta accreta spectrum disorders without placenta previa.

The number of cases of placenta accreta spectrum disorder has been increasing with the increase in in vitro fertilization and cesarean deliveries. In addition, placenta accreta spectrum without placenta previa is difficult to diagnose before delivery and sometimes requires a hysterectomy because of heavy bleeding. We have devised a uterus-preserving technique (referred to as the tourniquet, uterine inversion, and placental dissection procedure) for such cases. First, the bleeding is stopped by the tourniquet method, the uterus is relaxed with nitroglycerin, and the uterus is inverted to expose the adhesion site. After that, the placenta is detached by sharp dissection under direct visualization, and the detached areas are sutured, and then the tourniquet and internal rotation are released. This technique does not require advanced skills. Thus, a surgeon could avoid performing a hysterectomy and have a greater chance of uterus preservation when encountering massive hemorrhage caused by unpredictable placenta accreta spectrum without placenta previa in either cesarean deliveries or vaginal deliveries.

Prevention of fetal brain injury in category II tracings.

INTRODUCTION: With category II fetal heart rate tracings, the preferred timing of interventions to prevent fetal hypoxic brain damage while limiting operative interventions remains unclear. We aimed to estimate fetal extracellular base deficit (BDecf ) during labor with category II tracings to quantify the timing of potential interventions to prevent severe fetal metabolic acidemia. MATERIAL AND METHODS: A longitudinal study was conducted using the database of the Recurrence Prevention Committee, Japan Obstetric Compensation System for Cerebral Palsy, including infants with severe cerebral palsy born at ≥34 weeks' gestation between 2009 and 2014. Cases included those presumed to have an intrapartum onset of hypoxic-ischemic insult based on the fetal heart rate pattern evolution from reassuring to an abnormal pattern during delivery, in association with category II tracings marked by recurrent decelerations and an umbilical arterial BDecf ≥ 12 mEq/L. BDecf changes during labor were estimated based on stages of labor and the frequency/severity of fetal heart rate decelerations using the algorithm of Ross and Gala. The times from the onset of recurrent decelerations to BDecf 8 and 12 mEq/L (Decels-to-BD8, Decels-to-BD12) and to delivery were determined. Cases were divided into two groups (rapid and slow progression) based upon the rate of progression of acidosis from onset of decelerations to BDecf 12 mEq/L, determined by a finite-mixture model. RESULTS: The median Decels-to-BD8 (28 vs. 144 min, p < 0.01) and Decels-to-BD12 (46 vs. 177 min, p < 0.01) times were significantly shorter in the rapid vs slow progression. In rapid progression cases, physicians' decisions to deliver the fetus occurred at ~BDecf 8 mEq/L, whereas the "decisions" did not occur until BDecf reached 12 mEq/L in slow progression cases. CONCLUSIONS: Fetal BDecf reached 12 mEq/L within 1 h of recurrent fetal heart rate decelerations in the rapid progression group and within 3 h in the slow progression group. These findings suggest that cases with category II tracings marked by recurrent decelerations (i.e., slow progression) may benefit from operative intervention if persisting for longer than 2 h. In contrast, cases with sudden bradycardia (i.e., rapid progression) represent a challenge to prevent severe acidosis and hypoxic brain injury due to the limited time opportunity for emergent delivery.

Challenges to Widespread Use of Fertility Preservation Facilities for Pediatric Cancer Patients in Japan.

Purpose: Although fertility preservation for pediatric cancer patients is becoming more widespread in Japan, some facilities do not provide sufficient information regarding fertility. This study aimed to elucidate the problems pertaining to the lack of information about fertility among patients. Methods: Based on a 2020 survey, seminars addressing fertility preservation were held from the Designated Pediatric Cancer Care Hospitals in each of the seven blocks in Japan to their partner hospital (pediatric cancer hospitals). The seminar consisted of lectures and group discussions, and a questionnaire was also administered after each seminar. Results: In the group discussions, a lack of explanations to patients and explanatory materials for children were cited as issues by many facilities. The survey results revealed a lack of material explaining fertility preservation and a lack of knowledge among health care providers. There were also many requests to use the patient explanation videos presented at the seminar. Conclusion: The results indicate that further education for health care providers by seminar and other sources and enhancement of explanatory materials are important for fertility preservation in pediatric cancer hospitals in Japan.

Investigation of an efficient method of oocyte retrieval by dual stimulation for patients with cancer.

Purpose: To examine the optimal timing of second ovarian stimulation using the dual stimulation method for good ovarian responders with cancer undergoing oocyte retrieval for fertility preservation. Methods: A retrospective analysis was conducted using data from 69 patients with cancer who underwent oocyte retrieval for fertility preservation at four Japanese institutions during 2010-2021. Twenty-two patients underwent two oocyte retrievals for fertility preservation. We studied the relationship between the initial number of oocytes retrieved via dual stimulation and risk of ovarian enlargement as well as the appropriate waiting interval between the end of the first ovarian stimulation and beginning of the second ovarian stimulation. Results: The risk of ovarian enlargement was high when the initial number of oocytes retrieved via dual stimulation was ≥5. An 8-day waiting interval may be more effective for performing a second ovarian stimulation oocyte retrieval in these cases, although the difference was not significant. Conclusions: This study provides one policy for effectively managing ovarian enlargement and timing of second ovarian stimulation during oocyte retrieval via the dual stimulation method for patients with cancer undergoing fertility preservation. If more facilities implement this procedure, more oocytes may be obtained in a short period for fertility preservation purposes.