Department of Obstetrics and Gynecology, McGill University, Montreal, Quebec, Canada.
The Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Hum Reprod. 2022 Jul 30;37(8):1739-1745. doi: 10.1093/humrep/deac148.
Are deliveries following IVF with a thinner endometrium associated with adverse perinatal outcomes and placental findings?
Live births following IVF with a thinner endometrium are associated with an increased rate of placental-mediated obstetric complications and lower birthweight, while the placentas are notable for gross anatomical and histological malperfusion lesions.
Past studies have noted a higher rate of adverse outcomes on deliveries following IVF with a thinner endometrium, mainly placental-associated complications. However, no study to date has investigated placental histopathology in such cases.
STUDY DESIGN, SIZE, DURATION: This was a retrospective cohort study of 1057 deliveries following IVF, between 2009 and 2017. All placentas were sent to pathology irrelevant of pregnancy complication status, per protocol at our institution.
PARTICIPANTS/MATERIALS, SETTING, METHODS: Live singleton births from a tertiary university hospital after IVF were compared between patients for whom embryo transfer was performed with an endometrium <9 mm (thinner endometrium group) and patients with an endometrium ≥9 mm (control group). Placental pathologic findings were categorized according to the Amsterdam Placental Workshop Group Consensus. Outcomes were placental findings, including anatomic, inflammatory, vascular malperfusion and villous maturation lesions, as well as obstetric and perinatal outcomes. Continuous and categorical variables were compared as appropriate, and multivariate regression and linear analyses were employed to control for confounders.
A total 292 cases in the thinner endometrium group, and 765 in the control group were compared. Maternal demographics were non-significant between the groups, except for main fertility indication was more commonly diminished reserve in patients with a thinner endometrium and less commonly male factor, P = 0.003. Higher rates of fresh transfers were noted in the control group, while the thinner endometrium group was notable for higher rates of blastocyte transfers. After adjustment for confounders, deliveries in the thinner endometrium group were associated with an overall higher rate of main placental-mediated complications, 22.9% versus 15.2%, P = 0.003, and significantly lower birthweight, β -100.76 g (-184.4-(-17.0)). Placentas in the thinner endometrium group were notable for reduced thickness and a higher rate of bilobated placentas. Placental histology in the thinner endometrium group demonstrated a higher rate of maternal malperfusion lesions.
LIMITATIONS, REASONS FOR CAUTION: The study was limited by its retrospective design and lack of data regarding prior uterine surgery. In addition, sample size was limited for detection of differences in outcomes of rarer occurrence and for analysis as per a stricter definition of thin endometrium.
Excess obstetric risks should be taken into consideration while planning an embryo transfer with a thinner endometrium. Further studies are needed to assess the yield of cycle cancellation and the effect of potential preventive measures such as Micropirin treatment.
STUDY FUNDING/COMPETING INTEREST(S): No funding was used and the authors report no conflicting interests.
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接受体外受精（IVF）后子宫内膜较薄的分娩是否与围产期不良结局和胎盘发现有关？
接受体外受精（IVF）后子宫内膜较薄的活产与胎盘介导的产科并发症发生率增加和出生体重降低有关，而胎盘在大体解剖和组织学灌注不良病变方面明显。
过去的研究表明，接受体外受精（IVF）后子宫内膜较薄的分娩不良结局发生率较高，主要与胎盘相关并发症有关。然而，迄今为止，尚无研究调查此类病例的胎盘组织病理学。
研究设计、大小和持续时间：这是一项回顾性队列研究，纳入了 2009 年至 2017 年期间进行的 1057 例 IVF 后分娩。所有胎盘均按照我院的方案，根据协议发送至病理科，无论妊娠并发症状态如何。
参与者/材料、设置、方法：比较了在大学附属三级医院接受 IVF 后进行单胎活产的患者，胚胎移植时子宫内膜<9mm（子宫内膜较薄组）和子宫内膜≥9mm（对照组）。胎盘病理发现根据阿姆斯特丹胎盘工作组共识进行分类。结果为胎盘发现，包括解剖、炎症、血管灌注不良和绒毛成熟病变，以及产科和围产儿结局。适当比较连续和分类变量，并采用多元回归和线性分析来控制混杂因素。
在较薄的子宫内膜组中比较了 292 例病例，在对照组中比较了 765 例病例。两组患者的母体人口统计学特征无显著差异，但子宫内膜较薄患者的主要生育指征更常见于储备减少，而较少见于男性因素，P=0.003。对照组中新鲜转移的比例较高，而较薄的子宫内膜组中胚胎转移的比例较高。调整混杂因素后，较薄的子宫内膜组的总体主要胎盘介导的并发症发生率较高，为 22.9%比 15.2%，P=0.003，出生体重明显降低，β-100.76g（-184.4-（-17.0））。较薄的子宫内膜组的胎盘厚度降低，双叶胎盘的发生率较高。较薄的子宫内膜组的胎盘组织学显示母体灌注不良病变的发生率较高。
局限性、谨慎的原因：该研究受到其回顾性设计和缺乏关于既往子宫手术的数据的限制。此外，由于罕见结局的检测和更严格的薄型子宫内膜定义下的分析所需的样本量有限，因此无法检测到结局差异。
在计划进行子宫内膜较薄的胚胎转移时，应考虑到额外的产科风险。需要进一步研究以评估周期取消的效果以及潜在预防措施（如 Micropirin 治疗）的效果。
研究资金/利益冲突：未使用任何资金，作者报告无利益冲突。
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