A decade-long study following Irish mothers suggests that the mental health benefits of breastfeeding may extend well beyond the postnatal period, highlighting a possible long-term link between infant feeding and maternal well-being.
Study: Breastfeeding and later depression and anxiety in mothers in Ireland: a 10-year prospective observational study. Image credit: Nastyaofly/Shutterstock.com
In a recent study published in BMJ Open, researchers examined whether breastfeeding is associated with a lower likelihood of mothers experiencing anxiety and depression in later life. They found that Irish women who had breastfed were less likely to report anxiety or depression over the 10-year follow-up period.
Why breastfeeding may influence mothers’ long-term mental health
Breastfeeding is well known to benefit both the infant and the mother’s physical health, including a reduced risk of infection in infants and lower rates of cardiovascular disease, cancer, and diabetes in mothers. Growing evidence also links breastfeeding to improved infant mental health, cognitive development, and long-term well-being.
For maternal mental well-being, the correlation between breastfeeding and decreased postnatal depression is well established, with stronger effects observed for exclusive breastfeeding. Anxiety and depression frequently co-occur, and both have been linked to poorer breastfeeding outcomes.
Biological mechanisms underlying this relationship may involve lactation hormones such as oxytocin, which promotes bonding, reduces anxiety, and supports stress regulation through the hypothalamic-pituitary-adrenal axis. While the link between breastfeeding and mental health after giving birth is well documented, little is known about whether these associations extend beyond the postnatal period.
A 10-year cohort study examining lifetime breastfeeding patterns
Given the established correlation between postnatal depression and poorer long-term mental health, researchers aimed to investigate whether breastfeeding is associated with anxiety and depression later in women’s reproductive lives. They used data from a cohort that originated from a randomized controlled trial investigating a low–glycemic index diet during pregnancy.
Women were initially recruited from a maternity hospital in Dublin during their second pregnancy and followed at multiple time points up to 10 years postpartum. The current analysis included 168 multiparous women with complete lifetime data on breastfeeding and mental health at the 10-year follow-up. Women who were pregnant or breastfeeding at that time were excluded.
Breastfeeding exposure was assessed using validated infant feeding questionnaires administered at 10 years. Measures included whether the participants had ever breastfed, the number of weeks of any breastfeeding, the number of weeks of exclusive breastfeeding, and the cumulative breastfeeding duration of at least 12 months. Mental health outcomes were based either on self-reported diagnoses of depression or anxiety or on reported use of antidepressant medications, which was used as a proxy for depression or anxiety. However, the indication for medication use was not recorded and may have included non-psychiatric reasons.
Potential confounders included age, education, socioeconomic status, parity, smoking, alcohol consumption, physical activity, menopausal status, diet, and baseline well-being, as measured using established indices. Logistic regression modeling was used to assess associations between breastfeeding and mental health outcomes, adjusting for baseline age, baseline well-being, physical activity, and alcohol intake at the end of the study.
Breastfeeding linked to lower depression and anxiety over time
At the 10-year follow-up, participants were 42.4 years old on average, with most remaining premenopausal and highly educated. Nearly three-quarters (72.6 %) of the participants reported having breastfed at some point. Over their lifetimes, the median duration of exclusive breastfeeding was 5.5 weeks, while the median duration of any breastfeeding was 30.5 weeks. Over one-third had breastfed for at least 12 months across their lifetime.
Depression or anxiety was reported by 13.1 % of women at the end of the study and by 20.8 % at one or more points during the study period. Women reporting depression or anxiety were generally younger, had lower baseline well-being scores, and had a higher probability of smoking at the end of the study. Importantly, they were significantly less likely to report breastfeeding and had significantly shorter durations of both exclusive and total breastfeeding.
After adjusting for baseline differences and alcohol intake, ever breastfeeding was associated with lower odds of anxiety and depression at the 10-year follow-up. When depression or anxiety was considered across the full study period, ever breastfeeding, longer exclusive breastfeeding, and cumulative breastfeeding of at least 12 months were all linked to a reduced likelihood of anxiety and depression. Each additional week that women breastfed exclusively was associated with a small but significant reduction in risk.
Breastfeeding may offer lasting mental health advantages for mothers
This study found that breastfeeding, particularly longer exclusive and cumulative durations, was associated with a lower likelihood of anxiety and depression over 10 years. These findings extend previous research on postnatal mental health and suggest that breastfeeding may be linked to longer-term psychological well-being. Potential explanations include biological effects of lactation hormones, reduced risk of metabolic disease, and protection against postnatal depression, which itself predicts later mental health problems.
Key strengths include the long follow-up period, rich dataset, and adjustment for multiple confounders in a healthy baseline population. However, the study’s limitations include its small sample size and relatively homogenous cohort from a single Dublin hospital. Reliance on self-reported mental health and the use of antidepressant medication as a proxy outcome may bias results, and due to the observational design, causality could not be inferred, and unmeasured confounding may remain.
Overall, the findings suggest that breastfeeding may be associated with a reduced risk of long-term maternal mental health problems and highlight the need for larger, more diverse studies to validate these associations.
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Journal reference:
McNestry, C., O’Reilly, S.L., Twomey, P.J., Crowley, R.K., Callanan, S., Kasemiire, A., Douglass, A., Delahunt, A., McAuliffe, F.M. (2026). Breastfeeding and later depression and anxiety in mothers in Ireland: a 10-year prospective observational study. BMJ Open 16(1). DOI: 10.1136/bmjopen-2024-097323. https://bmjopen.bmj.com/content/16/1/e097323
