Rising temperatures caused by climate breakdown are causing great distress to the fetuses of pregnant farmers, who are among the worst affected by global warming.
A study found that the fetuses of women working in fields in The Gambia showed an increase in heart rate and a decrease in blood flow to the placenta as conditions got hotter. The women, who do much of the farm work and work during pregnancy, told the scientists that temperatures had risen noticeably over the past decade.
There is already strong evidence that extreme heat leads to increases in stillbirth, preterm birth and low birth weight, but this data comes from rich, temperate countries. The new study focuses for the first time on subsistence farmers in a tropical country where increasing extreme heat is a serious problem.
Hundreds of millions of people worldwide, including mothers, are expected to be exposed to extreme heat even if the global temperature is kept below the internationally agreed limit of 1.5°C above pre-industrial levels.
The research is the first step in understanding why fetuses suffer when expectant mothers are stressed by heat. Possible causes include sweating, which causes dehydration, and the draining of blood and oxygen from the placenta to the mother’s skin to cool the body. The scientists want to provide evidence of measures to protect expectant mothers and fetuses, such as: B. the cultivation of trees to give shade to women and crops.
dr Ana Bonell, from the Division of The Gambia’s Medical Research Council and London School of Hygiene & Tropical Medicine, who led the research, said: “Our study found that pregnant subsistence farmers are often exposed to extreme heat in excess of recommended outdoor working limits , and that this can have a significant impact on their health and the health of their babies.
“We were very shocked to find that this was the case for 34% of visits [to the fields]there was this effect on the fetus.”
A series of studies published in January found that the The climate crisis is damaging the health of fetuses, babies and young children worldwide. Scientists discovered that increased heat is linked to rapid weight gain in babies, increasing the risk of obesity later in life. Higher temperatures have also been linked to premature births, which can have lifelong health implications, and increased hospitalizations for young children.
The research, published in the journal Lancet Planetary Health, included 92 pregnant subsistence farmers in a rural district of The Gambia. During the seven-month study period, the average air temperature during work hours was 33.5 °C (92.3 °F).
The scientists also measured the humidity, the women’s temperature and the heart rate of expectant mothers and fetuses. The researchers found that if the woman’s body temperature and heart rate increased by one category on a heat stress index, the risk of fetal stress increased by 20%. Fetal distress was indicated by a heart rate greater than 160 beats per minute or decreased placental perfusion as measured by ultrasound.
The team also found that when a measure of heat stress increased by 1°C, the risk of fetal distress increased by 17%. It increased by 12% even after accounting for increases in the woman’s temperature and heart rate, suggesting other factors affecting the fetus. These can include dehydration, low blood flow in the placenta, or heat-related inflammation.
Heat illnesses were found to be widespread among worker bees, with nearly 60% reporting at least one symptom during field assessments. Symptoms included headache, dizziness, weakness, muscle cramps, vomiting and dry mouth.
To address the growing problem of heat stress, Bonell said, “First of all, I would just recommend stopping burning fossil fuels — that’s the big picture.”
Individual measures could include cooling with ice packs, resting in the shade, and ensuring women can stop work if symptoms appear. Community-level action could include financial support programs that allow women to work less during pregnancy and agroforestry, she said.
