中文摘要：

目的分析妊娠不同时期应激生活事件暴露、孕期体重增加过多及剖宫产是否会增加产后泌乳启动延迟的风险。方法对2017名待产初产妇在分娩前进行问卷调查,以了解孕妇的一般人口统计学信息,并评价孕早、中、晚期应激生活事件的发生和对精神影响的程度。在分娩后记录分娩方式、孕周和新生儿出生情况。在产后72小时询问泌乳情况。对研究变量进行单因素和多因素Logistic回归分析,计算各研究变量的RR值。结果初产妇产后泌乳启动延迟发生率为9.5%。单因素分析显示,孕早期应激生活事件暴露、孕期BMI增幅≥7.6、分娩方式为剖宫产的产妇发生产后泌乳延迟的RR值分别为1.72（95%CI0.97～3.04）、1.93（95%CI1.23～2.94）和1.35（95%CI1.20～1.53）。多因素分析显示,上述3个因素调整后RR值分别为1.97（95%CI1.09～3.55）、1.64（95%CI1.07～2.54）和1.32（95%CI1.17～1.49）。结论孕早期应激生活事件暴露、孕期增重过多、剖宫产会对产后早期泌乳产生影响,孕早期暴露于应激生活事件是自然分娩产妇发生产后泌乳延迟的重要危险因素。

英文摘要：

Objective To evaluate the effect of severe life events at first,second and third trimester,excessive weight gain during pregnancy and caesarean section on the delayed onset of lactation.Methods The effect of life stressful event during different gestational age in a total of 2017 parturient women giving birth in hospitals was assessed with reliable questionnaires.Demographic characteristics,history of pregnancy,BMI at early pregnancy and antepartum and the delivery outcomes including gestational age at birth,mode of delivery and the condition of babies were collected by interviewing or from medical charts.Lactation guidance was provided and the data on the onset of lactation were collected in hospitals within 72 hours after parturition.The onset of lactation was defined by the perception of mothers on the fullness of the breast.Univariate and multivariate logistic regression analyses were performed after controlling maternal age,registered permanent residency and educational level.Results Delayed onset of lactation occurred in 9.5% of 2017 women and was associated with exposure to severe life events at the first trimester （crude RR = 1.72,95% CI 0.97 - 3.04,adjusted RR = 1.97,95% CI 1.09 - 3.55）,increasing of BMI ≥7.6 during pregnancy （crude RR =1.93,95%CI 1.23 -2.94,adjusted RR =1.64,95%CI 1.07 -2.54） and caesarean section （ crude RR = 1.35,95% CI 1.20 - 1.53,adjusted RR = 1.32,95% CI 1.17 - 1.49 ）.Conclusion Success on early lactation is strongly influenced by potentially modifiable factors,such as exposure to severe life events in the first gestational age,excessive weight gain during pregnancy and caesarean section.