Heavily pregnant Sonari toils under the burning sun in fields dotted with bright yellow melons in Pakistan’s Jacobabad, which last month became the hottest city on Earth.

Her 17-year-old neighbour Waderi, who gave birth a few weeks ago, is back working in temperatures that can exceed 50 degrees Celsius (122 degrees Fahrenheit), with her newborn lying on a blanket in the shade nearby so she can feed him when he cries.

“When the heat is coming and we are pregnant, we feel stressed,” said Sonari, who is in her mid-20s.

These women in southern Pakistan and millions like them around the world are at the searing edge of climate change.

Pregnant women exposed to heat for prolonged periods of time have a higher risk of suffering complications, an analysis of 70 studies conducted since the mid-1990s on the issue found.

For every 1C (1.8F) rise in temperature, the number of stillbirths and premature deliveries increases by about 5 percent, according to a study carried out by several research institutions globally and published in the British Medical Journal in September 2020.

Women are especially vulnerable to rising temperatures in poor countries on the front lines of climate change because many have little choice but to work through their pregnancies and soon after giving birth, according to interviews with more than a dozen female residents in the Jacobabad area as well as half a dozen development and human rights experts.

South Asia has suffered unseasonably hot temperatures in recent months. An extreme heatwave that scorched Pakistan and India in April was 30 times more likely to happen due to climate change, according to scientists at World Weather Attribution, an international research collaboration.

Jacobabad’s roughly 200,000 residents are well aware of its reputation as one of the world’s hottest cities. “If we go to hell, we’ll take a blanket” is a common joke told in the area.

Sonari, who is in her 20s, and Waderi work alongside about a dozen other women, several of them pregnant, in the melon fields about 10km (6.2 miles) from Jacobabad’s centre.

They begin work each day at 6am with a short afternoon break for housework and cooking before returning to the field to work until sundown. They describe leg pains, fainting episodes and discomfort while breastfeeding.

“It feels like no one sees them, no one cares about them,” aid worker Liza Khan said more broadly about the plight facing many women in Jacobabad and the wider Sindh region which straddles the border of Pakistan and India.

The harsh conditions facing many women were brought into tragic focus on May 14, the day temperatures in Jacobabad hit 51C (124F), making it the world’s hottest city at that time.

Widespread poverty and frequent power cuts mean many people cannot afford or use air conditioning or at times even a fan to cool down.

Potential strategies recommended by experts include providing clean-energy stoves to replace open-fire cooking, offering women’s medical and social services during early morning or evening hours when it is cooler and replacing tin roofs with cooler material in white to reflect solar radiation away from the home.

Most residents of Jacobabad rely on water deliveries, which can cost between a fifth and an eighth of a household’s meagre income. Still, it is often not enough, and some families are forced to ration.

For young mother Razia, the sound of her six-month-old Tamanna crying in the afternoon heat was enough to persuade her to pour some of her precious water over the baby. She then sat Tamanna in front of a fan, and the child was visibly calmer, playing with her mother’s scarf.

Local officials said water shortages were partly due to electricity cuts, which means water cannot be filtered and sent via pipes throughout the city.

Climate Change Minister Sherry Rehman told Reuters news agency that women were likely to bear the brunt of rising temperatures which continue to scorch the country, adding that climate change policies in the future needed to address the specific needs of women.

“A megatrend like climate change … poses a significant threat to the wellbeing of unempowered women in rural areas and urban slums,” she said. “Pakistani women, especially on the margins, will be impacted the most.”

Rubina, who is Razia’s neighbour, fries onions and okra over an open fire, explaining she usually felt dizzy in the heat and tried to soak herself in water each time she cooked to prevent herself from fainting. There was not always enough water to do so, though.

“Most of the time, it ends before it’s time to buy more and we must wait,” Rubina said as she supervised her children and grandchildren sharing a cup of water. “On the hot days with no water, no electricity, we wake up and the only thing we do is pray to God.”