MS is more common in women than in men. Research shows that this may at least in part be due to a relationship between sex hormones and MS in women. For example, the onset of MS is rare before the onset of menstruation or after menopause, and relapse rates for women with established MS often decrease during pregnancy or when they are breastfeeding.
Breastfeeding has previously been linked to a number of health benefits to the mother, including reducing the risk of developing ovarian cancer, type 2 diabetes, and breast cancer. In this new research study published in the journal Neurology Dr Annette Langer-Gould and her colleagues from Kaiser Permanente Southern California, USA, found evidence to suggest that breastfeeding can also protect against the development of MS.
In this research, around 750 women with or without MS or Clinically Isolated Syndrome (CIS, a potential precursor to MS), and aged 18 or older from Southern California were interviewed. A range of data regarding socio-economic status, pregnancies, smoking, breastfeeding and other information related to menstruation was collected and analysed.
The researchers found that breastfeeding for a total of more than 15 months reduced the risk of developing MS or CIS or reduced the rate of relapses compared to breastfeeding for a total of up to 4 months. They also found that the younger a woman was when she first started menstruating increased her risk of developing MS or CIS. None of the other factors they investigated were associated with an increased or decreased risk of developing MS or CIS.
Importantly, the amount of time spent breastfeeding was cumulative, i.e. after one or more pregnancies, and not limited to a single pregnancy. This result is not an association of being pregnant more often, as people with and without MS had similar numbers of pregnancies.
It is important to note that this relationship between breastfeeding and a reduced risk of developing MS was determined as an average across the whole population of women studied. At the individual level, the risk factors for developing MS vary enormously and a different combination of risk factors may be more or less dominant in any given individual (you can read more what we know about the causes of MS in our comprehensive article. Also, breastfeeding is not recommended when taking certain medications, and should be discussed with your prescribing practitioner.
How and why this amount of time breastfeeding protects against MS or CIS later in life is not yet clear and requires further investigation. However as the authors state ‘this study provides more evidence that women who are able to breastfeed their infants should be supported to do so. Among other maternal and infant health benefits, breastfeeding may reduce the mother’s future risk of developing MS’.