Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA.
Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA.
Am J Clin Nutr. 2021 Aug 2;114(2):813-821. doi: 10.1093/ajcn/nqab089.
Preterm birth (PTB) remains a leading cause of neonatal mortality and long-term morbidity. Individual factors have been linked to PTB risk. The impact of a healthy lifestyle, with multiple modifiable prenatal factors, remains unknown.
We aimed to examine the associations of preconceptional and early-pregnancy low-risk modifiable factors (individually and in combination) with PTB risk.
This prospective cohort study included 2449 women with singleton pregnancies in the Pregnancy Environment and Lifestyle Study. PTB was defined as ultrasound-confirmed obstetric estimate-based gestational age at delivery <37 wk. A set of low-risk modifiable factors were identified: healthy weight (prepregnancy BMI: 18.5-24.9 kg/m2) based on clinical measurements and high-quality diet (Alternate Healthy Eating Index-Pregnancy score ≥75th percentile) and low-to-moderate stress during early pregnancy (Perceived Stress Scale score <75th percentile) assessed at gestational weeks 10-13. Poisson regression estimated adjusted relative risk (aRR) of PTB in association with individual and combined low-risk modifiable prenatal factors, adjusting for sociodemographic, clinical, and other prenatal factors.
One hundred and sixty women (6.5%) delivered preterm. Risk of PTB was lower among women who had a healthy weight (aRR: 0.58; 95% CI: 0.39, 0.86), high-quality diet (aRR: 0.68; 95% CI: 0.39, 0.99), and low-to-moderate stress (aRR: 0.60; 95% CI: 0.41, 0.88). Women with 1, 2, or 3 low-risk modifiable prenatal factors compared with none had a 38% (aRR: 0.72; 95% CI: 0.45, 1.16), 51% (aRR: 0.49; 95% CI: 0.29, 0.84), or 70% (aRR: 0.30; 95% CI: 0.13, 0.70) lower PTB risk, respectively. Associations of having ≥1 low-risk factor with PTB risk were more pronounced for medically indicated than for spontaneous PTB and for late than for early or moderate PTB. Associations also varied by race or ethnicity, although with overlapping 95% CIs.
A healthy prenatal lifestyle with multiple low-risk modifiable factors was associated with lower risk of PTB. Our findings may inform multicomponent preconceptional or early-pregnancy prevention strategies to mitigate PTB risk.
早产 (PTB) 仍然是新生儿死亡和长期发病的主要原因。个体因素与 PTB 风险有关。健康生活方式的影响，包括多个可改变的产前因素，其影响仍不清楚。
我们旨在研究孕前和孕早期低风险可改变因素（单独和组合）与 PTB 风险的关联。
这项前瞻性队列研究包括 2449 名在妊娠环境和生活方式研究中怀有单胎妊娠的女性。PTB 的定义是超声确认的产科估计基于分娩时的孕龄<37 周。确定了一组低风险可改变的因素：健康体重（孕前 BMI：18.5-24.9 kg/m2），基于临床测量和高质量饮食（替代健康饮食指数-妊娠评分≥75 百分位）和孕早期（妊娠 10-13 周时）的低至中度压力（感知压力量表评分<75 百分位）。泊松回归估计了与单个和组合的低风险可改变的产前因素相关的 PTB 的调整后相对风险（aRR），调整了社会人口统计学、临床和其他产前因素。
有 160 名女性（6.5%）早产。与体重健康（aRR：0.58；95%CI：0.39，0.86）、高质量饮食（aRR：0.68；95%CI：0.39，0.99）和低至中度压力（aRR：0.60；95%CI：0.41，0.88）的女性相比，PTB 的风险较低。与没有低风险可改变的产前因素相比，有 1、2 或 3 个低风险可改变的产前因素的女性的 PTB 风险分别降低了 38%（aRR：0.72；95%CI：0.45，1.16）、51%（aRR：0.49；95%CI：0.29，0.84）或 70%（aRR：0.30；95%CI：0.13，0.70）。具有≥1 个低风险因素与 PTB 风险的关联对于医学指征的早产比自发性早产更为明显，对于晚期早产比早期或中期早产更为明显。关联也因种族或民族而异，尽管 95%CI 重叠。
孕前生活方式健康，有多个低风险可改变的因素与 PTB 风险降低有关。我们的发现可能为多组分孕前或孕早期的预防策略提供信息，以减轻 PTB 的风险。
