Climate Change Linked to Lower Birth Weight in African Babies
When pregnant women in Africa work the fields during extremely hot days and live in areas with scant rainfall, their babies have a lower birth weight, according to a first-of-its-kind study.
Such babies are often more vulnerable to illnesses and more likely to develop disabilities. Climatologists involved in the study anticipate more hot days in Africa as climate change accelerates, with East Africa suffering from shorter rainy seasons. That could result in more babies with lower birth weight.
“It could be stress related to dehydration, or if the woman is working in the fields in high temperatures, then it’s heat stress,” said Kathryn Grace, lead author of the study and a health geographer with the University of Utah. “These factors do affect fetal development.”
Grace and her colleagues conducted the study, which compared birth weight with temperature and precipitation levels for 70,000 newborns in19 African countries from 1986 to 2010.
The countries included Burkina Faso, Ethiopia, Kenya, Liberia, Mali, Nigeria, Rwanda, Sierra Leone, Tanzania, Uganda, and Zimbabwe.
The researchers looked at the range of temperatures and the amount of rainfall in the vicinity of a baby for the year before each birth. They found that just one extra day of temperatures above 100 degrees Fahrenheit corresponded to a reduction in birth weight of about one gram. On average, birth weights fell about 4 percent.
The amount of rain also affected babies and mothers.
“High rainfall can lead to a spread of diseases like malaria, while low rainfall can result in a lack of clean drinking water and sufficient food production,” Grace said.
The researchers used data from the United States Agency for International Development’s Famine Early Warning System and other agencies to correlate the factors that affected birth weight. Grace also went to Burkina Faso to interview women about the impact of hot weather on their babies.
The USAID system uses climate forecasts to predict problems in food production and how to position aid designed to increase education and access to clean water and food. Grace said such assistance is undermined by climate change.
“We talk about increasing women’s education—but weight loss from lack of knowledge did not hurt the birth weight of babies as much as environmental factors did,” she said. “The poorest women who were already marginalized often ended up having low-birth-weight babies.”