Some hospital patients in mid Wales who are treated in England may face longer journeys.
Changes are planned to maternity and paediatric care in Shropshire with a unit moving from Shrewsbury to Telford - an extra 20 miles away for some.
Each year more than 300 babies from Wales are born at the Royal Shrewsbury Hospital.
Two public meetings will hear patients' concerns but Shropshire's NHS Trust said it wanted to improve services.
A meeting was held in Llanidloes, Powys, last Friday which was attended by 250 people.
Mother-of-three Helen Jervis, from nearby Newtown, spent five weeks at the hospital before the birth of her eldest son Ryan.
She had pre-ecalampsia so before that had to regularly travel for 45 minutes for blood tests and monitoring.
"I personally think that it's going to put children's lives at risk," she said.
"I don't think they realise how far we have to travel.
"We, as an action group, completely agree reconfiguration does have to go ahead but the proposals they are putting forward are dangerous.
"I think the best option would be to keep it in the centre of Shropshire."
A group of senior doctors has written a joint letter supporting the proposals and saying change is necessary otherwise there will be "dire consequences" for all health care services in Shropshire.
Signed by 16 clinicians from the area, it reads: "The maternity building at Royal Shrewsbury Hospital is in a very poor state and at risk of significant failure which puts the future of safe and effective paediatric maternity and neonatal services at risk.
"We are very close to securing significant improvements and developments in some services and will lose these if we are not able to centralise emergency and inpatient surgical care.
"The reconfiguration proposals will offer significant improvements in the quality of care for many patients.
"The window of opportunity to implement the required changes is closing and without them the future for health services in Shropshire looks increasingly bleak."
Two public meetings are being held for those with concerns.
The first takes place at 1900 GMT on Wednesday at the Royal Oak Hotel in Welshpool and the other at the same time on Thursday at the Elephant and Castle in Newtown.
Shropshire's NHS Trust said the majority of treatment would not be affected and the current maternity unit was cramped and out of date.
Head of midwifery Cathy Smith, said they would not be looking at the changes if they did not think services for mothers would improve.
"When they do get to us we want them to be in a building that provides the right kind of equipment, the right number of beds and that when they do arrive after a long journey we've got a bed to put them in, a theatre free and a neonatal unit that can offer them the opportunity to be with their babies."