There is a lot of talk about climate change, but little is said about some specific phenomena and the impact on people. Climate change and pregnancy are one of the things that should be warned about more. For example, climate changes – especially extreme heat and extreme weather conditions are harder on pregnant women. Pregnant women are at greater risk of experiencing heat stroke and heat exhaustion. High temperatures can increase the risk of miscarriage, stillbirth and premature birth.
The risks of illness and death caused by heat waves are higher, and for pregnant women, who may have a higher risk of high blood pressure and eclampsia and preeclampsia, this represents an additional burden. Extreme weather conditions that are accompanied by storms, hurricanes and floods also increase the stress on pregnant women.
Heat directly affects the proper development of the baby during pregnancy
Heat increases the risk of stillbirth, premature birth and low birth weight, according to a study (1) published in 2023 . Pathomechanisms through which heat stress interferes with pregnancy maintenance are still unclear, but new evidence emphasizes that the endocrine system is severely affected.
The American CDC warns that temperatures of 39 o C and above, especially monitoring with high humidity , are risky because they cause exhaustion and dehydration, and add that maternal circulation helps protect the developing baby, however, in very hot environments, a pregnant woman's temperature can rise. In some cases, it's linked to birth defects and other reproductive problems, the CDC points out.
According to a study by Stefanie Papatheodorou, a lecturer in epidemiology at the Harvard Chan School, high temperatures are associated with disorders in fetal development. She and her team followed a group of about 9,500 pregnant women from eastern Massachusetts.
“We discovered that the parameters of the head, which characterize the size of the brain, are especially affected by temperature, and even more so in early pregnancy. They were more sensitive than other structures in the body.” said Dr. Papatheodorou.
“To see if these heat-related changes in fetal structures lead to actual neurodevelopmental outcomes, we are now conducting a larger study. We received a major grant to do a national analysis of more than 1.4 million pregnancies between 2000 and 2014, using Medicaid data. This study will focus on uncovering the relationship between climate factors, air pollution and neurodevelopmental outcomes. We hope that within a year we will have results“, she added.
Currently, a study is being conducted in the USA, the aim of which is to determine how much heat increases the risk of spontaneous abortions. The study, launched in May and funded by the National Institute of Child Health and Human Development, is led by Amelia Wesselink, a reproductive and environmental epidemiologist at Boston University. In 2022, her team published a study (2) in which it was shown that the rate of spontaneous abortions is higher during the month of August compared to February.
Indirect impact of heat: worse health care, air pollution and infectious diseases
Pregnant women and newborns are especially sensitive to stress and diseases that floods, caused by extreme weather conditions due to climate change, can intensify. In many areas, the risk of malaria increases after floods because mosquitoes that breed in standing water are more widespread and there is a higher probability of death and complications for pregnant women or when it comes to newborns and small children in general.
Prenatal care, birth support, newborn screenings and vaccinations are more difficult to provide when health centers are closed or overwhelmed by a natural disaster.
High temperatures can also cause fires, such as those this year in Canada, with air pollution that further harms pregnant women and the fetus, warned the American Society of Pediatricians.
Polluted air is a particular risk for premature birth and even for autism spectrum disorders.
- Yüzen D, Graf I, Diemert A, Arck PC. Climate change and pregnancy complications: From hormones to the immune response. Front Endocrinol (Lausanne). 2023 Apr 5;14:1149284. doi: 10.3389/fendo.2023.1149284. PMID: 37091849; PMCID: PMC10113645.
- Wesselink AK, Wise LA, Hatch EE, Mikkelsen EM, Savitz DA, Kirwa K, Rothman KJ. A Prospective Cohort Study of Seasonal Variation in Spontaneous Abortion. Epidemiology . 2022 May 1;33(3):441-448. doi: 10.1097/EDE.0000000000001474. PMID: 35213511.
Jelena Kalinić, MA in comparative literature and graduate biologist, science journalist and science communicator, has a WHO infodemic manager certificate and Health metrics Study design & Evidence based medicine training. Winner of the 2020 EurekaAlert (AAAS) Fellowship for Science Journalists. Short-runner, second place in the selection for European Science journalist of the year for 2022.