I’ve repeatedly noted that the evidence for the purported benefits of breastfeeding for babies is weak, conflicting and riddled with confounders. The actual benefits of breastfeeding are tiny, limited to 8% fewer colds and 8% fewer episodes of diarrheal illness across the entire population of infants in their first year.
The evidence for purported maternal benefits is even worse.
You’d never know it from the way that lactivists tout maternal benefits of breastfeeding. According to a recent article in Health, breastfeeding purportedly leads to these benefits for mothers:
[pullquote align=”right” cite=”” link=”” color=”” class=”” size=””]Considering the disabling limitations of the data, there is NO basis for ANY claims of maternal benefit from breastfeeding.[/pullquote]
- Easier weight loss after birth
- Lower risk of breast cancer
- Lower risk of ovarian cancer
- Lower risk of endometrial cancer
- Lower risk of type II diabetes
- Lower risk of heart disease
But that’s not what the scientific evidence shows.
Consider this new review of the impact of breastfeeding on maternal health conducted by Alison Stuebe, MD and colleagues on behalf of the Agency for Healthcare Research and Quality (AHRQ).
I created this table to summarize their findings on a long list of diseases:
With the exception of ovarian cancer, there is insufficient evidence or only low quality evidence to support an association between breastfeeding and these diseases. And an association does not necessarily mean causation. For example, we know that the risk of ovarian cancer is related to the number of ovulatory cycles experienced by a woman. Breastfeeding can decrease lifetime ovulatory cycles and therefore may lead to a lower risk of ovarian cancer. But use of the birth control pill ALSO decreases lifetime ovulatory cycles and can provide the same benefit.
The key point is this: there is NO high quality evidence that even associates breastfeeding with the lower risk of these diseases, let alone evidence that breastfeeding causes a reduced incidence of these diseases.
But that doesn’t stop Stuebe and the other authors from making claims that are not supported by their own evidence:
Our conclusions related to the maternal benefits of breastfeeding suggest that breastfeeding is associated with lower rates of breast cancer, ovarian cancer, hypertension, and type 2 diabetes. The potential to improve maternal health could be highlighted as a rationale for improving rates of breastfeeding by health care and public health practitioners. For cardiometabolic outcomes, it has been hypothesized that lactation “resets” maternal metabolism after pregnancy, thereby reducing cardiovascular disease risk.
Wait, what? They JUST SHOWED that the evidence doesn’t support that claim and yet they are making it anyway?
This despite the fact that they acknowledge:
We concluded that low SOE supports the association between breastfeeding and reduced hypertension; however, primarily because of heterogeneity in outcome measures and study limitations, we concluded that evidence was insufficient to reach a conclusion about cardiovascular disease.
This is a perfect example of the way in which lactation professionals ignore the evidence in order to claim benefits for breastfeeding that don’t exist.
The authors admit that any claim of maternal benefits for breastfeeding is undermined by their inability to correct for confounding variables.
Several other factors may be at work. First, women in very high income countries who choose to and successfully breastfeed are typically better educated, wealthier, and more likely to engage in other beneficial health behaviors. Moreover, it is plausible that, rather than breastfeeding preventing poor maternal health, poor maternal health may prevent breastfeeding…
In their conclusion, the authors state:
The identified associations between breastfeeding and improved maternal health outcomes are supported by evidence from observational studies, which cannot determine cause and effect relationships.
Not really. The truth is that there is only insufficient and low quality evidence to support an association between maternal benefits and breastfeeding, with the exception of ovarian cancer. When corrected for confounding variables these associations may disappear entirely. In any case, an association is NOT causation. In light of these disabling limitations, there is NO basis for asserting ANY maternal benefit from breastfeeding.
