Ovarian stimulation is associated with a higher risk of low birth weight. However, the precise mechanisms by which ovarian stimulation increases the chances of low birth weight remain unclear. In this mouse model study, in vivo developed blastocysts that were not exposed to gonadotropins were transferred into pseudopregnant females that had mated naturally (the control group), pseudopregnant females that had been administered a low dose of ovulation-stimulating hormone (the L-SO group) and pseudopregnant females that had been administered a high dose of ovulation-stimulating hormone (the H-SO group). The embryo implantation rate and fetal weight were significantly lower in the L-SO and H-SO groups than in the control group. The density of Dolichos biflorus agglutinin (DBA)⁺ uterine natural killer (uNK) cells in the decidua basalis was significantly lower in the L-SO and H-SO groups than in the control group. Ovarian stimulation also downregulated a variety of cytokines related to uNK cells that are involved in placental angiogenesis and trophoblast invasion. Collectively, our findings indicate that ovarian stimulation impairs DBA⁺ uNK cell density in the decidua basalis, which may downregulate uNK-related cytokine secretion and influence placental angiogenesis and restrict fetal growth in mice.

中文翻译：

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卵巢刺激通过失调小鼠子宫自然杀伤细胞来减少胎儿生长

卵巢刺激与低出生体重的风险较高有关。然而，卵巢刺激增加低出生体重机会的确切机制仍不清楚。在这项小鼠模型研究中，体内发育的未暴露于促性腺激素的囊胚被转移到已自然交配的假孕雌性（对照组）、已施用低剂量促排卵激素（L-SO）的假孕雌性体内。组）和接受高剂量促排卵激素的假孕女性（H-SO组）。L-SO和H-SO组的胚胎着床率和胎儿体重显着低于对照组。双花凝集素 (DBA)的密度⁺L-SO 和 H-SO 组基底蜕膜中的子宫自然杀伤 (uNK) 细胞明显低于对照组。卵巢刺激还下调了与uNK细胞相关的多种细胞因子，这些细胞因子参与胎盘血管生成和滋养层侵袭。总的来说，我们的研究结果表明卵巢刺激会损害基底蜕膜中的DBA ^{+ uNK 细胞密度，这可能会下调 uNK 相关细胞因子的分泌，影响胎盘血管生成并限制小鼠的胎儿生长。}