Breastfeeding is important for a mother’s health.
For example, there’s convincing evidence that not breastfeeding increases a mother’s risk of breast and ovarian cancer.
There’s also growing evidence that breastfeeding is important for a mother’s cardiovascular health.
Breastfeeding is a normal physiological process following pregnancy. It’s not surprising then, that when normal physiological processes are disrupted (e.g. breastfeeding doesn’t occur or is cut short) there are increased health risks.
One way in which breastfeeding appears to be important for a mother’s cardiovascular health is in terms of her blood pressure.
Breastfeeding and High Blood Pressure
So what does the research show us about breastfeeding and blood pressure?
Not Breastfeeding Increases The Risk Of High Blood Pressure
Quality observational studies have found that not breastfeeding increases the risk of high blood pressure.
A 2015 cross-sectional study of more than 9,000 women was conducted in China; it found that women who did not breastfeed were 18% more likely to develop high blood pressure than women who breastfed. This study controlled for possible confounding factors, including age, body mass index, waist to hip ratio, working status, educational level, drinking, smoking, family history of high blood pressure, age at menarche, menopause, oral contraceptive use, age of child-bearing, and postpartum body mass index.
A large prospective cohort study in 2013 looked at almost 75,000 Australian women, and showed a dose-response effect of breastfeeding on later high blood pressure risk in women between the ages of 45 and 65+. This study found that not breastfeeding increased the risk of later high blood pressure by 11%. It also found a dose dependency response, meaning that the less that breastfeeding occurred, the higher the risk of developing high blood pressure.
Another quality large prospective cohort study of over 55,000 women, in 2011, found that mothers who didn’t breastfeed, or breastfed for less than 6 months, had about a 20% increased risk of high blood pressure compared with mothers who breastfed for one year per child. It was determined that 8% of all high blood pressure in women could be attributed to not breastfeeding for a year per child. This study controlled for smoking status, body mass index, pregnancy complications, physical activity, alcohol consumption, diet, family history of high blood pressure, oral contraceptive use, non-narcotic analgesic use, and race.
Not Breastfeeding And Women Who Had High Blood Pressure During Pregnancy
In addition, a recent prospective cohort study showed that not breastfeeding is associated with an increased risk of developing high blood pressure among women who had high blood pressure during pregnancy (but not preeclampsia). This study controlled for possible confounding factors such as maternal age, race, education, pre-pregnancy weight, and time since giving birth.
The strengths of this study were that it collected data prospectively, not retrospectively, and was representative of overweight and obese women (those who are at the highest risk of high blood pressure problems in pregnancy). The weaknesses of the study were: the small number of participants; the lack of long term follow-up; and the fact that the results cannot be generalised to non-overweight/obese populations of women.
Because women who have high blood pressure during pregnancy are at greater risk of high blood pressure and cardiovascular disease later in life, breastfeeding could be particularly important in helping to attenuate this risk.
From the research, it appears that not breastfeeding is a risk factor for high blood pressure. The next step would be a systematic review, to collate the available evidence, and reach overall conclusions.