More than 100,000 heavily pregnant women face the risk of infection and disease in the aftermath of the flooding in Pakistan, Save the Children has warned.
The aid agency said at least half a million expectant mothers had been affected by the floods, with tens of thousands of newborn babies and women in potential danger in the coming months.
It added many expectant mothers would be forced to give birth in temporary shelters or tents, with no access to clean water or healthcare.
Matt Wingate of Save the Children said: "We know that mums are already giving birth in the flimsiest of shelters, only metres from dirty floodwater.
"This presents appalling risks in terms of disease and infection, and ultimately poses a serious threat to the lives of mums and their newborn babies."
Before this disaster, the country already had a high infant mortality rate, with one in 20 babies dying before they were a month old.
Mr Wingate added: "We're going all-out to reach as many people as possible. We've established fixed and mobile health clinics and are treating hundreds of people every day, including pregnant women and new mothers."
The charity's aid workers have assisted pregnant women, carrying them across swollen rivers to safety, and delivered life-saving care to women giving birth in risky situations.
It said it had so far reached more than 160,000 people through emergency medical care and distribution of food, tents, shelter kits, hygiene kits and other supplies.