Delayed onset of lactogenesis (DOL) is an important cause for reduced exclusive breastfeeding rates. The dietary inflammatory index (DII) has been shown to be associated with a variety of adverse health outcomes, but the relationship with DOL is not well understood.

Understanding DII levels of women in the third trimester and exploring the impact on DOL.

A convenience sampling method was used to select women in the third trimester who underwent routine obstetric examinations in the First Affiliated Hospital of Anhui Medical University from December 2023 to June 2024 as the study subjects and were followed up until 72 hours postpartum, and the maternal self-perceived breast distension method was used to determine whether they were in the DOL population. General demographic characteristics and information related to pregnancy and childbirth were collected using a general information questionnaire, a food frequency questionnaire (FFQ) was used to collect information on dietary intake and calculates the DII, and the delivery and postpartum data questionnaire were used to collect relevant information about labor and postpartum. Exploring the relationship between DII and DOL using binary Logistic regression analysis and stratified the factors of age, preconception BMI, and presence of gestational diabetes mellitus.

A total of 228 questionnaires were distributed and 217 questionnaires were validly returned, with an effective recovery rate of 95.2%. Among them, 68 (31.3%) with DOL. The DOL and the non-DOL mothers were statistically different in terms of the number of pregnancies, the quality of sleep, gestational weight gain, and the presence of mother-infant separation after delivery (P<0.05). The pregnant women in the high DII group had a higher incidence of DOL than those in the middle and low DII groups according to the three quartiles of DII scores from smallest to largest (P<0.017). The results of binary Logistic regression analysis showed that the risk of DOL was 2.817 times higher in the high DII group than in the low DII group (95%CI=1.244-6.381, P=0.013). In the third trimester group of women aged<35 years with preconception BMI<24.0 kg/m², the risk of DOL in women with high DII levels was 3.144 times (95%CI=1.346-7.344, P<0.05) and 2.666 times (95%CI=1.072-6.630, P<0.05) higher than in women with low DII levels, respectively.

There was a correlation between DII and DOL, with higher DII increasing the risk of DOL, especially in the group of women in late pregnancy who are <35 years of age and with preconception BMI <24.0 kg/m². Maternal and child health care providers should provide individualized dietary guidance to pregnant women, increase the intake of anti-inflammatory diets to reduce the incidence of DOL and increase the rate of exclusive breastfeeding.

泌乳启动延迟（DOL）是纯母乳喂养率降低的重要原因。膳食炎症指数（DII）已被证实与各种不良健康结局有关，但与DOL的关系尚不十分清楚。

了解孕晚期女性DII水平，探究其对DOL的影响。

采用便利抽样法选取2023年12月—2024年6月在安徽医科大学第一附属医院常规产检的孕晚期女性作为研究对象并追踪至产后72 h，采用产妇自感乳胀法确定是否为DOL人群。采用一般资料调查表收集孕妇的一般人口学特征及孕产相关信息；采用食物频率问卷调查表（FFQ）收集膳食摄入信息，并计算DII；采用分娩和产后资料调查表收集分娩和产后相关信息。采用二元Logistic回归分析探究DII和DOL的关系并对年龄、孕前BMI和是否有妊娠期糖尿病因素进行分层分析。

共发放问卷228份，回收有效问卷217份，有效回收率为95.2%。其中68人（31.3%）发生DOL。DOL产妇和非DOL产妇在孕次、孕期睡眠质量、妊娠期增重、产后是否有母婴分离方面比较，差异有统计学意义（P<0.05）。根据三分位数法将DII分为低、中、高3组，高DII组孕妇DOL发生率高于中DII组和低DII组（P<0.017）。二元Logistic回归分析结果显示，高DII组发生DOL的风险是低DII组的2.817倍（95%CI=1.244~6.381，P=0.013）。在年龄<35岁、孕前BMI<24.0 kg/m²的妊娠晚期女性群体中，高DII组的女性发生DOL的风险分别是低DII组女性的3.144倍（95%CI=1.346~7.344，P<0.05）、2.666倍（95%CI=1.072~6.630，P<0.05）。

DII和DOL之间存在相关性，较高的DII会增加DOL发生风险，尤其是年龄<35岁和孕前BMI<24.0 kg/m²的孕晚期女性群体。妇幼保健人员应对孕妇群体进行个性化饮食指导，增加抗炎饮食的摄入量以降低DOL发生率，提高纯母乳喂养率。