Breastfeeding linked to reduced maternal depression and anxiety up to ten years

Breastfeeding may lower mothers' later life risks of depression and anxiety for up to 10 years after pregnancy, suggest the findings of a small observational study, published in the open access journal BMJ Open.

The observed associations were apparent for any, exclusive, and cumulative (at least 12 months) breastfeeding, the study shows.

Breastfeeding is associated with lower risks of postnatal depression and anxiety, but it's not clear if these lowered risks might persist in the longer term, say the researchers.

To find out, they tracked the breastfeeding behavior and health of 168 second time mothers who were originally part of the ROLO Longitudinal Birth Cohort Study for 10 years.

All the women had given birth to a child weighing under 4 kg and they and their children had check-ups 3 and 6 months, and 2, 5, and 10 years after birth by which time the mothers' average age was 42.

At each check-up, the mothers completed a detailed health history questionnaire. This asked whether they had been diagnosed with, and treated for, depression/anxiety. They also provided information on potentially influential factors, including diet and physical activity levels.

At the check-ups, the mothers provided information on: whether they had ever breastfed or expressed milk for 1 day or more; total number of weeks of exclusive breastfeeding; total number of weeks of any breastfeeding; and cumulative periods of breastfeeding of less or more than 12 months.

Nearly three quarters of the women (73%; 122) reported having breastfed at some point. The average period of exclusive breastfeeding lasted 5.5 weeks and that of any breastfeeding for 30.5 weeks. More than a third (37.5%; 63) reported cumulative periods of breastfeeding adding up to at least 12 months.

Twenty two (13%) of the women reported depression/anxiety at the 10-year check-up, with a further 35 (21%) reporting depression or anxiety at any time point.

Those reporting depression/anxiety at the 10 year check-up were younger, less physically active, and had lower wellbeing scores at the start of the study than those who didn't report this. Those women reporting depression and anxiety at any time point differed only by age at the start of the study.

Analysis of the data showed that women experiencing depression and anxiety 10 years after pregnancy were less likely to have breastfed and had shorter periods of any or exclusive breastfeeding over their lifetime.

Each week of lifetime exclusive breastfeeding was associated with a 2% lower likelihood of reporting depression and anxiety, after accounting for potentially influential factors, including alcohol intake.

This is an observational study, and as such, no firm conclusions can be drawn about cause and effect. And the researchers acknowledge that participants were relatively few in number, not ethnically or socially diverse, and that the study relied on personal recall rather than objective measures of depression/anxiety.

Nevertheless, they write: "We suggest there also may be a protective effect of successful breastfeeding on postpartum depression and anxiety, which in turn lowers the risk of maternal depression and anxiety in the longer term." 

They explain: "The likelihood is that the association is multifactorial, as many socioeconomic and cultural factors influence both breastfeeding and mental health in addition to the impact of health history. Additionally, women with a prior history of depression and anxiety are at risk of lower breastfeeding success, compounding the association but in the reverse direction."

They conclude: "We know that improving breastfeeding rates and duration can improve lifetime health outcomes, reducing population level disease burden and resulting in significant healthcare savings.

"The possibility that breastfeeding could further reduce the huge burden of depression on individuals, families, healthcare systems and economies only adds to the argument for policymakers to improve breastfeeding support."