Opinion | Could Extreme Heat Make It Harder to Breastfeed?

As a family physician and lactation consultant, I often see patients who struggle to breastfeed. Usually, they blame themselves. Are they holding the baby wrong? Forgetting to alternate sides?

The actual problem might have nothing to do with the breastfeeding person, and, in some cases, may be the result of factors beyond individual control.

I practice in rural Kansas, in an area surrounded by dairy farms. Here, it is common knowledge that cattle don’t do well in the heat. Cows are mammals — milk producers — just like us. When it gets too hot, cows produce less milk, and their milk is less nutritious.

If extreme heat affects lactation in dairy cows, are humans affected, too? The problem is, we just don’t know, because the issue has not been properly researched.

We do know that extreme heat has a detrimental impact on the pregnant body and fetus, causing an increase in preterm births, stillbirths, and low birth weight. Excessive heat causes stress on the body, and it is worth studying whether rising temperatures also have an impact on human milk production. Already, 60% of mothers do not breastfeed for as long as they intend to. This failure in planned behavior should lead us to look at all of the factors — including the physical environment — that could lead a parent to stop nursing.

Any reductions in breastfeeding could be harmful for infants and children. Human milk is still the ideal nourishment for babies; it works powerfully to strengthen the immune system and provides other benefits that scientists are still discovering. Breastfed babies are healthier; they are less prone to ear and stomach infections, and have lower risk of asthma, obesity, type 1 diabetes, and sudden infant death syndrome.

As the planet warms, we need to understand — and mitigate — the effects of extreme heat on human health, including pregnancy and potentially the postpartum. And we need to do so quickly. The World Meteorological Organization predicts that the next 5 years will be the hottest ever recorded. Extremely hot summers, which happened rarely 50 years ago, are now common. That means a mother today is breastfeeding in an environment that is very different from that of her grandmother, and which will only become more distinct.

The dairy industry, at least, is taking extreme heat seriously. Farmers track the volume and nutritional content of their cows’ milk production, to understand how heat affects the animals and what changes need to be made. Dairy farms have strategies in place — shade, ventilation, evaporative cooling — to alleviate heat stress for their cows.

If farmers are taking measures to keep their cattle cool, shouldn’t we have a better understanding of the best practices to care for human mothers and infants exposed to the same heat?

We need more research to determine the impact of extreme heat on breastfeeding mothers and infants. We also need actionable plans to mitigate heat in our homes and communities. That might mean parks and other green spaces, cooling centers, and help for families that cannot afford air conditioning. More broadly, it means reducing the greenhouse gas emissions that are heating up the planet.

On warm nights, I often sit on my porch, reviewing medical charts and listening to cattle mooing in the distance. When it’s especially hot, the animals’ cries become an unpleasant wail. Those sounds are Mother Nature’s not-so-subtle way of saying that things aren’t quite right; it’s getting too hot for comfort.

I think, then, of my postpartum patients and their struggles with breastfeeding, their discomfort and exhaustion in the unrelenting heat. The fact is, it’s getting too hot for all of us.

Brianna Clark, DO, is an osteopathic physician and certified lactation counselor based in Kingwood, Texas; she practices in Kansas. Clark is a 2023 Climate Health Equity Fellow with the Medical Society Consortium on Climate and Health.