Abstract：
BACKGROUND: The IMPACT BCN trial-a parallel-group randomized clinical trial where 1221 pregnant women at high risk for small-for-gestational age (SGA) newborns were randomly allocated at 19- to 23-week gestation into three groups: Mediterranean diet, Mindfulness-based Stress reduction or non-intervention-has demonstrated a positive effect of Mediterranean diet and Stress reduction in the prevention of SGA. However, the mechanism of action of these interventions remains still unclear. The aim of this study is to investigate the effect of Mediterranean diet and Stress reduction on placental volume and perfusion.
METHODS: Participants in the Mediterranean diet group received monthly individual and group educational sessions, and free provision of extra-virgin olive oil and walnuts. Women in the Stress reduction group underwent an 8-week Stress reduction program adapted for pregnancy, consisting of weekly 2.5-h and one full-day sessions. Non-intervention group was based on usual care. Placental volume and perfusion were assessed in a subgroup of randomly selected women (n = 165) using magnetic resonance (MR) at 36-week gestation. Small placental volume was defined as MR estimated volume <10th centile. Perfusion was assessed by intravoxel incoherent motion.
RESULTS: While mean MR placental volume was similar among the study groups, both interventions were associated with a lower prevalence of small placental volume (3.9% Mediterranean diet and 5% stress reduction vs. 17% non-intervention; p = 0.03 and p = 0.04, respectively). Logistic regression showed that small placental volume was significantly associated with higher risk of SGA in both study groups (OR 7.48 [1.99-28.09] in Mediterranean diet and 20.44 [5.13-81.4] in Stress reduction). Mediation analysis showed that the effect of Mediterranean diet on SGA can be decomposed by a direct effect and an indirect effect (56.6%) mediated by a small placental volume. Similarly, the effect of Stress reduction on SGA is partially mediated (45.3%) by a small placental volume. Results on placental intravoxel incoherent motion perfusion fraction and diffusion coefficient were similar among the study groups.
CONCLUSIONS: Structured interventions during pregnancy based on Mediterranean diet or Stress reduction are associated with a lower proportion of small placentas, which is consistent with the previously observed beneficial effects of these interventions on fetal growth.
METHODS: Participants in the Mediterranean diet group received monthly individual and group educational sessions, and free provision of extra-virgin olive oil and walnuts. Women in the Stress reduction group underwent an 8-week Stress reduction program adapted for pregnancy, consisting of weekly 2.5-h and one full-day sessions. Non-intervention group was based on usual care. Placental volume and perfusion were assessed in a subgroup of randomly selected women (n = 165) using magnetic resonance (MR) at 36-week gestation. Small placental volume was defined as MR estimated volume <10th centile. Perfusion was assessed by intravoxel incoherent motion.
RESULTS: While mean MR placental volume was similar among the study groups, both interventions were associated with a lower prevalence of small placental volume (3.9% Mediterranean diet and 5% stress reduction vs. 17% non-intervention; p = 0.03 and p = 0.04, respectively). Logistic regression showed that small placental volume was significantly associated with higher risk of SGA in both study groups (OR 7.48 [1.99-28.09] in Mediterranean diet and 20.44 [5.13-81.4] in Stress reduction). Mediation analysis showed that the effect of Mediterranean diet on SGA can be decomposed by a direct effect and an indirect effect (56.6%) mediated by a small placental volume. Similarly, the effect of Stress reduction on SGA is partially mediated (45.3%) by a small placental volume. Results on placental intravoxel incoherent motion perfusion fraction and diffusion coefficient were similar among the study groups.
CONCLUSIONS: Structured interventions during pregnancy based on Mediterranean diet or Stress reduction are associated with a lower proportion of small placentas, which is consistent with the previously observed beneficial effects of these interventions on fetal growth.
摘要：
背景：IMPACTBCN试验-一项平行组随机临床试验，其中1221名处于小胎龄（SGA）新生儿高危的孕妇在妊娠19至23周时随机分为三组：地中海饮食，正念为基础的压力减少或不干预已经证明了地中海饮食和压力减少在预防SGA方面的积极作用。然而,这些干预措施的作用机制仍不清楚.这项研究的目的是研究地中海饮食和减少压力对胎盘体积和灌注的影响。
方法：地中海饮食组的参与者每月接受个人和团体教育课程，免费提供特级初榨橄榄油和核桃。减轻压力组的妇女接受了为期8周的适合怀孕的减轻压力计划，包括每周2.5小时和一个全天的会议。非干预组以常规护理为基础。在妊娠36周时使用磁共振（MR）对随机选择的女性（n=165）的亚组进行胎盘体积和灌注评估。小胎盘体积定义为MR估计体积<10百分位数。通过体素内不相干运动评估灌注。
结果：虽然研究组的平均MR胎盘体积相似，两种干预措施均与胎盘体积小的患病率较低相关(3.9%的地中海饮食和5%的压力减少与17%的非干预；分别为p=0.03和p=0.04）。Logistic回归显示，在两个研究组中，小胎盘体积与SGA的高风险显着相关（地中海饮食的OR为7.48[1.99-28.09]，压力减轻的OR为20.44[5.13-81.4]）。中介分析表明，地中海饮食对SGA的影响可以通过小胎盘体积介导的直接作用和间接作用（56.6％）来分解。同样，应激降低对SGA的影响部分由小胎盘体积介导(45.3%)。各组胎盘内不相干运动灌注分数和扩散系数的结果相似。
结论：基于地中海饮食或减轻压力的妊娠期结构化干预措施与小胎盘的比例较低有关。这与先前观察到的这些干预措施对胎儿生长的有益影响一致。
方法：地中海饮食组的参与者每月接受个人和团体教育课程，免费提供特级初榨橄榄油和核桃。减轻压力组的妇女接受了为期8周的适合怀孕的减轻压力计划，包括每周2.5小时和一个全天的会议。非干预组以常规护理为基础。在妊娠36周时使用磁共振（MR）对随机选择的女性（n=165）的亚组进行胎盘体积和灌注评估。小胎盘体积定义为MR估计体积<10百分位数。通过体素内不相干运动评估灌注。
结果：虽然研究组的平均MR胎盘体积相似，两种干预措施均与胎盘体积小的患病率较低相关(3.9%的地中海饮食和5%的压力减少与17%的非干预；分别为p=0.03和p=0.04）。Logistic回归显示，在两个研究组中，小胎盘体积与SGA的高风险显着相关（地中海饮食的OR为7.48[1.99-28.09]，压力减轻的OR为20.44[5.13-81.4]）。中介分析表明，地中海饮食对SGA的影响可以通过小胎盘体积介导的直接作用和间接作用（56.6％）来分解。同样，应激降低对SGA的影响部分由小胎盘体积介导(45.3%)。各组胎盘内不相干运动灌注分数和扩散系数的结果相似。
结论：基于地中海饮食或减轻压力的妊娠期结构化干预措施与小胎盘的比例较低有关。这与先前观察到的这些干预措施对胎儿生长的有益影响一致。
