Breastfeeding may lower mothers’ later life risks of depression and anxiety for up to 10 years after pregnancy, suggest the findings of an observational study, published in the open access journal BMJ Open.
The observed associations were evident for any, exclusive, and cumulative (at least 12 months) breastfeeding, the study shows.
It is known that breastfeeding reduces the risk 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 behaviour and health of 168 second time mothers who were originally part of the ROLO Longitudinal Birth Cohort Study for 10 years after pregnancy.
Corresponding author, Professor Fionnuala McAuliffe (Chair and Full Academic Professor of Obstetrics and Gynaecology, UCD School of Medicine and Director UCD Perinatal Research Centre), says: "The finding that breastfeeding may reduce mothers’ later life chance of depression and anxiety is very exciting and is another great reason to support our mothers to breastfeed."
The women were recruited from early pregnancy and they and their children had check-ups at 3 and 6 months, and 2, 5, and 10 years after birth, by which time their average age of mothers was 42 years.
At each check-up, the mothers completed a detailed health history questionnaire. This asked whether they had been diagnosed with, and treated for, depression and or anxiety. They also provided information on potentially influential factors, including diet and physical activity levels.
At these follow 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 lifetime periods of breastfeeding adding up to at least 12 months.
Some 22 (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.
Analysis of the data showed that women experiencing depression and anxiety at 10 years after pregnancy were less likely to have breastfed and had shorter durations 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, associations only can be relied upon.
Nevertheless, the team wrote: “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 said: “The likelihood is that the association is multifactorial, as many socioeconomic and cultural factors influence both breastfeeding and mental health. Additionally, women with a prior history of depression and anxiety are at risk of lower breastfeeding success, compounding the association.”
They said: “We know that improving breastfeeding rates and duration can improve mothers’ lifetime health outcomes in terms of less diabetes and heart disease and reduces at population level disease burden with resultant 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 further promote breastfeeding.”