Breastfeeding has Many Benefits for Women
First, I would like to address that the purpose of this article is to provide education about the benefits of nursing for mothers and nursing people. The goal is not to shame how you choose to feed your child. The choice to nurse is incredibly personal and nuanced and should not be subject to criticism.
Breast Cancer
Breast cancer is the most common cancer in women worldwide and there appears to be a clear correlation between nursing and reducing breast cancer risk. Exclusive nursing showed various relative risk reductions ranging from 15-53%, other studies suggesting it’s closer to 26-28% reduction in cancer risk. What is consistent across most studies is the protective benefits increase with prolonged nursing, meaning breastfeeding for more than 12 months. However, good news for anyone with a shorter breastfeeding journey, research shows that even nursing once is correlated with a 12-14% relative risk reduction of breast cancer.
The reduction in risk is thought to be because the breast cells change to produce milk after pregnancy reducing the susceptibility to carcinogenic effects such as estrogen. Pregnancy and nursing also prevent ovulation temporarily, called postpartum amenorrhea, which also reduces estrogen levels for the duration of time where menses is suspended. This ultimately reduces lifetime exposure to estrogen; these benefits increase with each subsequent pregnancy and period of post partum amenorrhea. Nursing also lowers blood levels of insulin. High levels of insulin can increase growth factor IGF-1 which promotes growth and prevents normal cell death in all tissues but also breast tissue.
Ovarian Cancer
Ovarian cancer is the seventh most common cancer in women worldwide. Again there appears to be a clear correlation between nursing and a reduction in risk for this disease. The correlation was also dose dependent meaning the longer you nurse, the greater the risk reduction. There was a 17% relative risk reduction in people who nursed less than 6 month, a 28% risk reduction in those who nursed for 6-12 months and lastly a 37% lower in those who nursed for more than 12 months.
It is hypothesized that the reduction in risk again is due to the decrease in life time exposure to estrogen due to pregnancy and prolongation of post partum amenorrhea from nursing. The same school of thought also applies for decreasing insulin levels and growth factors which contribute to cell growth including that of cancer cells.
Type II Diabetes
The majority of the robust studies looked predominantly at breast and ovarian cancer risk however there are fewer studies on type II diabetes and nursing. A 2013 study did see a relative risk reduction of 9% for each lifetime 12-month period of nursing.
Inconclusive Findings
There unfortunately is a lot of misinformation regarding all of the benefits of nursing. Many making claims that increased post partum weight loss is associated with nursing, along with improved blood pressure and reductions in post partum depression. The studies observing these correlations were not conclusive and didn’t show a clear relationship between these.
There is also misleading information that nursing decreases bone mineral density. This also was not supported by the literature. However, the importance of a good prenatal vitamin and evaluation dietary and supplemental calcium consumption in the post partum period, especially the first 6 months post partum when exclusively nursing is a wise and proactive approach.
Key Takeaway Messages
- Nursing even once conveys protection again breast cancer.
- Exclusive nursing for the first 6 months and longer durations of nursing seemingly provides even more protection against breast cancer and ovarian cancer.
- The WHO recommends exclusive nursing for the first 6 months of baby’s life and encourages continuing until age 2 and beyond.
Resources:
PMID: 28196329
PMID: 35126640
PMID: 26172878
PMID: 34322634
