Risk factors for placenta accreta spectrum in pregnancies conceived after frozen-thawed embryo transfer in a hormone replacement cycle.

OBJECTIVE: Assisted reproductive technology (ART), especially frozen-thawed embryo transfer (FET) in a hormone replacement cycle (HRC), is a risk factor for placenta accreta spectrum (PAS). This study aimed to clarify the risk factors for PAS related to the maternal background and ART techniques in pregnancies achieved after FET in an HRC. STUDY DESIGN: We performed a case-control study in two tertiary perinatal centres in Japan. Among 14,028 patients who delivered at ≥24 weeks of gestation or were transferred after delivery to two tertiary perinatal centres between 2010 and 2021, 972 conceived with ART and 13,056 conceived without ART. PAS was diagnosed on the basis of the FIGO classification for the clinical diagnosis of PAS or retained products of conception after delivery at ≥24 weeks of gestation. We excluded women with fresh embryo transfer, FET with a spontaneous ovulatory cycle, a donor oocyte cycle, and missing details of the ART treatment. Finally, among women who conceived after FET in an HRC, 62 with PAS and 340 without PAS were included in this study. Multivariate logistic regression models were used for case-control comparisons, with adjustment for maternal age at delivery, parity, endometriosis or adenomyosis, the number of previous uterine surgeries of caesarean section, myomectomy, endometrial polypectomy or endometrial curettage, placenta previa, the stage of transferred embryos, and endometrial thickness at the initiation of progestin administration. RESULTS: PAS was associated with ≥2 previous uterine surgeries (adjusted odds ratio, 3.57; 95 % confidence interval, 1.60-7.97) and the stage of embryo transfer (blastocysts: adjusted odds ratio, 2.89; 95 % confidence interval, 1.15-7.26). In patients with <2 previous uterine surgeries, PAS was associated with an endometrial thickness of <7.0 mm (adjusted odds ratio, 5.18; 95 % confidence interval, 1.10-24.44). CONCLUSION: Multiple uterine surgeries and the transfer of blastocysts are risk factors for PAS in pregnancies conceived after FET in an HRC. In women with <2 previous uterine surgeries, a thin endometrium before FET is also a risk factor for PAS in these pregnancies.

Relationship between nutrition and reproduction.

BACKGROUND: Recently, the relationship between nutrition and reproduction is being studied. In particular, when older women receive reproductive treatment, egg aging causes greater problems than organic factors. METHODS: This study investigated the relationship between nutrition and reproduction with a focus on factors that cause aging, including oxidation, glycation, and chronic inflammation. A large volume of data concerning each nutrient's relationship with reproductive medicine was collected from a number of observational studies. MAIN FINDINGS: The results showed that refined carbohydrates should be avoided and care should be taken to achieve proper intake of omega-3 fatty acids. Folic acid and vitamin D were also effective. For men, antioxidant measures are especially effective. The effects of antioxidants are related to insulin resistance, which causes chronic inflammation. CONCLUSION: Recent research has shown that rather than meal content, meal intervals are more important for improving insulin resistance. Future research should examine lifestyle-related nutrition factors and their relationships to reproductive treatment.