Climate health crisis: How extreme heat triggers premature births and pregnancy complications - The News International

Extreme heat events, heat storms and prolonged heatwaves driven by climate change have emerged as a serious global health crisis, placing pregnant women and newborns among the most vulnerable populations. Public health organizations, medical professionals and recent studies increasingly highlight the significant risks extreme temperatures pose to maternal and infant health.

The threats extend beyond immediate physical discomfort, encompassing biological vulnerabilities, adverse pregnancy outcomes, systemic healthcare barriers and long-term consequences for newborns.

Pregnancy brings substantial physiological changes that make it harder for the body to regulate its internal temperature.

Increased Cardiovascular Strain: Pregnancy naturally increases blood volume and heart rate. During extreme heat, the cardiovascular system must work harder to circulate blood towards the skin for cooling while maintaining adequate blood supply to the uterus and developing fetus.

Rapid Dehydration: Pregnant women have increased fluid requirements and are particularly vulnerable to dehydration during heatwaves. Dehydration can reduce blood flow to the placenta, trigger uterine contractions and impair the body's ability to regulate temperature through sweating.

Preterm Birth: Elevated maternal body temperatures and dehydration can increase the risk of early labour and premature delivery, defined as birth before 37 weeks of pregnancy. Premature birth can have lasting consequences for a child's health and development.

Low Birth Weight: Extreme heat exposure has been associated with restricted fetal growth and low birth weight (below 5.5 pounds), potentially affecting infant development.

Hypertensive Disorders: High temperatures may increase the risk of pregnancy-related blood pressure complications, including pre-eclampsia, a potentially life-threatening condition for both mother and child.

Stillbirth: Severe heat stress and impaired placental function have also been associated with an increased risk of stillbirth.

Some studies further suggest that extreme heat exposure during pregnancy may increase the risk of miscarriage and certain congenital abnormalities.

Although extreme heat affects pregnant women worldwide, its consequences are particularly severe in low- and middle-income countries, where access to cooling facilities, reliable electricity and climate-resilient infrastructure remains limited.

Millions of pregnant women, particularly those living in overcrowded urban settlements, have few options for escaping dangerous temperatures. Many also continue working in agriculture, manual labour and informal outdoor occupations throughout pregnancy, exposing themselves to prolonged heat stress.

Access to healthcare presents another major challenge. Extreme weather can disrupt transportation and essential infrastructure, making it harder for pregnant women to reach healthcare facilities for routine prenatal visits and emergency treatment. At the same time, heatwaves can increase demand for emergency medical services, placing additional pressure on already stretched healthcare systems.

International health organizations, including the World Health Organization (WHO), and global research partnerships warn that healthcare systems remain inadequately prepared to address the growing threat of extreme heat to maternal health.

Frontline healthcare workers need better training, specialised resources and clinical guidance to recognise and manage heat-related pregnancy complications.

Public health authorities are therefore calling for pregnant women to be explicitly included in heat-health action plans. Recommended measures include strengthening early-warning systems, expanding access to affordable cooling facilities and making maternal healthcare services more resilient to climate-related disruptions.

To the surprise of many medical professionals, studies from different parts of the world are revealing the extent to which extreme heat threatens pregnant women and their unborn children. Researchers are increasingly identifying links between heat exposure and complications ranging from miscarriage and congenital abnormalities to premature birth.

However, medical understanding of these risks is still developing, and healthcare professionals have often focused primarily on the immediate effects of extreme heat rather than its specific consequences for maternal and fetal health.

The scale of the threat is also growing. According to the figures cited in the research, the 1960s recorded approximately 50 heat storms, with the largest covering around 6% of the planet. In contrast, more than 665 heat storms have already been recorded this decade. 

The largest reportedly extended across nearly 85% of the planet during its year-long lifespan, exposing virtually the entire global population to its effects.