左 勝則

ABSTRACT Background Thyroid autoimmunity (TAI) is prevalent among women of reproductive age and has been associated with impaired fertility; however, its effects on ovarian reserve and infertility treatment outcomes remain controversial. Methods A narrative review was performed using PubMed to identify clinical and experimental studies addressing TAI, ovarian reserve, premature ovarian insufficiency (POI), and infertility treatment outcomes. Results Clinical evidence suggests that TAI is associated with modestly reduced AMH levels in adult women, although the magnitude of this decline appears insufficient to indicate imminent POI. In contrast, adolescents with TAI may exhibit elevated AMH. Observational studies describe a frequent coexistence of TAI and POI; however, Mendelian randomization analyses suggest that POI may predispose to TAI rather than the reverse. Mechanistic studies show that thyroid hormones act directly on ovarian cells via thyroid hormone receptors, while immune‐mediated pathways involving cytokines, oxidative stress, and anti‐ovarian antibodies may contribute to follicular dysfunction. Evidence regarding assisted reproductive technology outcomes in euthyroid TAI remains inconsistent. Conclusion TAI may exert a subtle influence on ovarian reserve through complex endocrine and immune mechanisms, with age‐specific variation. Although AMH alterations are observed, their clinical relevance for fertility and treatment outcomes remains unclear, highlighting the need for longitudinal studies.

ABSTRACT Purpose To summarize assisted reproductive technology (ART) data for 2023 collected through the Japan Society of Obstetrics and Gynecology registry. Methods and Results 625 out of 638 registered ART facilities took part in the study, documenting 561 664 treatment cycles and 85 048 newborns (+3.3% and +10.2% increases from 2022). The average age of women undergoing treatment was 37.3 years (standard deviation: 4.8); 205 986 cycles (36.7%) involved women aged ≥ 40 years. Among fresh cycles, oocyte retrieval was performed in 281 665 cycles, including 168 343 freeze‐all cycles (59.8%). A total of 2329 pregnancies and 3375 newborns resulted from in vitro fertilization and intracytoplasmic sperm injection cycles, yielding 1772 and 2502 newborns, respectively. The overall rates for single embryo transfer (SET) and singleton delivery were 80.5% and 96.5%. Frozen–thawed embryo transfer accounted for 271 361 cycles, resulting in 109 850 pregnancies and 80 774 newborns, with a SET rate of 84.7% and a singleton delivery rate of 96.3%. Conclusions In 2023, the second year of insurance coverage, the registry recorded the highest numbers of treatment cycles and newborns. Effective registry systems planned for 2026 will enable comprehensive evaluation of emerging trends in Japanese ART practice.

ABSTRACT Aim To describe how decreased fetal movement (DFM) was managed in patients with fetomaternal hemorrhage (FMH) and to evaluate the diagnostic limitations of this condition in real‐world settings. Methods This retrospective cohort study included individuals who developed FMH with cerebral palsy from the Japanese nationwide cerebral palsy registry between 2009 and 2022. We investigated whether patients experienced DFM or were prenatally diagnosed with FMH. Furthermore, we assessed how DFM was managed. Results This study included 57 patients who developed FMH with cerebral palsy, and none were prenatally diagnosed with FMH. DFM was present in 43/57 (75.4%) patients. A sinusoidal pattern was observed in 29/57 (50.9%) patients, and elevated middle cerebral artery peak systolic velocity (MCA‐PSV) was detected in 6/10 (60.0%) patients who underwent this test. Of the 43 patients with DFM, 42 (97.7%) sought medical care for this symptom; however, only 12 (27.9%) underwent examinations on the same day as the onset of DFM, and 9 (20.9%) were admitted on that same day. Furthermore, 6/43 (14.0%) were instructed to stay home after telephone consultation or medical examination for this symptom. In five of the 43 patients (11.6%) who experienced DFM, the initial non‐stress test was reactive. However, all these patients eventually developed either a non‐reactive or non‐reassuring fetal status. Conclusions DFM was prevalent among pregnancies complicated by FMH; however, it was often inadequately managed, resulting in diagnostic delays. Furthermore, fetal heart rate monitoring and MCA‐PSV evaluations had diagnostic limitations. To facilitate early treatment, clinicians need to promptly assess preceding DFM while recognizing the limitations of existing tests.