Mid-Pregnancy Maternal Anxiety Mediates the Association Between Maternal Chronotype and Breastfeeding Duration

<b>Background:</b> Maternal chronotype, maternal sleep, and breastfeeding practices are separately associated with maternal mood. However, it is not known if maternal mood mediates the associations between maternal chronotype or maternal sleep and breastfeeding duration. <b>Objective:</b> To investigate whether maternal mood mediates the associations of maternal chronotype and maternal prenatal sleep with breastfeeding duration in a multiethnic cohort of Singaporean mothers. <b>Methods:</b> In a prospective cohort study, caregivers of term-born, singleton infants (<i>N</i> = 340) completed the Horne-Östberg Morningness-Eveningness Questionnaire (MEQ; 54 months), Pittsburgh Sleep Quality Index (PSQI; 26 weeks gestation), Edinburgh Postnatal Depression Scale (EPDS; 26-28 weeks gestation) and State-Trait Anxiety Inventory (STAI-state, STAI-trait; 26-28 weeks gestation) and reported breastfeeding practices from 3 weeks to ≥12 months. Regression and mediation analyses were adjusted for maternal age, parity, maternal education, ethnicity, pre-pregnancy BMI, and mode of delivery. <b>Results:</b> Morningness was significantly associated with a longer breastfeeding duration (<i>β</i> = 0.02, <i>p</i> = 0.037) and lower maternal anxiety symptoms (STAI-state: <i>β</i> = -0.19, <i>p</i> = 0.006 and STAI-trait: <i>β</i> = -0.18, <i>p</i> = 0.004). Lower maternal anxiety symptoms were significantly associated with a longer breastfeeding duration (STAI-state: <i>β</i> = -0.02, <i>p</i> = 0.003; STAI-trait: <i>β</i> = -0.02, <i>p</i> = 0.016). STAI-state, but not STAI-trait or EPDS, mediates the association between maternal chronotype and breastfeeding duration (<i>β</i>_indirect = 0.004 (0.0004, 0.009)). Maternal mood did not mediate the association between maternal night sleep duration and breastfeeding duration. <b>Conclusions:</b> Maternal state-anxiety constitutes a behavioral pathway through which maternal chronotype influences breastfeeding duration. Strategies to target maternal anxiety in pregnant women with eveningness tendencies to promote breastfeeding duration are warranted.