The government should have done more to help the NHS cope with the increase in foreign-born mothers using maternity services, the Conservatives say.
Annual spending on maternity care for such women in England has risen by more than £200m in the past decade.
Tory health spokesman Stephen O'Brien said the government was "guilty of no forward planning for the impact of immigration on public services".
The Department of Health said it was a "national priority" to improve care.
The BBC found that immigration has raised the birth rate so fast that some units have closed, so that midwives could be moved to areas of urgent need.
Mr O'Brien told BBC Radio 5 Live: "The real issue here is the government were rightly warned of this impending situation for years and now we find that they're guilty of no forward planning for the impact of immigration on public services - particularly the health service and particularly maternity services - and they were warned.
LIVE BIRTHS BY COUNTRY OF BIRTH OF MOTHER
Births by British-born mothers down 44,000
Births by all foreign-born mothers up 64,000
Births by mothers born in Eastern Europe up 15,000
Births by mothers born in Indian subcontinent up 11,000
Births by mothers born in Africa up 8,000
"It was only in April last year that we were criticising Patricia Hewitt, the then secretary of state, that this situation was not under control and she absolutely said it was and that whilst birth rates were rising the government was still claiming they were moving towards one-to-one midwifery and it's more midwives that we need."
When Labour came to power, the NHS spent around £1bn a year on maternity services in England, with one baby in eight delivered to a foreign-born mother.
Ten years on, spending has risen to £1.6bn, with almost one baby in four delivered to a mother born overseas.
While the number of babies born to British mothers has fallen by 44,000 in total since the mid-1990s, the figure for babies born to foreign mothers has risen by 64,000 - a 77% increase which has pushed the overall birth-rate to its highest level for 26 years.
The Royal College of Midwives also expressed concern at the lack of staff.
General secretary Dame Karlene Davis said: "The Royal College of Midwives believes that all women should be given access to maternity care in this country, irrespective of their immigration status.
"Midwives want to give them the best possible care, as they do with all women, but the continuing shortage of midwives means this is becoming increasingly difficult."
Health Secretary Alan Johnson last week announced extra funding for maternity services that will increase over the next three years to reach an additional £122m annually.
He said the funds would help ensure women get a choice over where to give birth, improve flexibility of maternity services' opening hours and increase the number of midwives and support staff.
A Department of Health spokesman said: "We have this year made improving maternity services a national priority for the NHS.
"People who move from the European Economic Area to take up permanent lawful residence in the UK as workers, students or on a self-sufficient basis are considered part of the local population and are entitled to maternity care."
However, the chief executive of the National Childbirth Trust, Belinda Phipps, said the government needed to look again at the way it allocated funds to maternity units.
"If you don't speak English very well or you don't understand how our system works, or you come from a country where perhaps TB is more prevalent, then there are greater costs to treat you and to support you in having a baby.
"What the health service needs to do is to recognise that each baby that's born has a cost associated with it and when more babies are born there needs to be more resources and they need to keep an eye on the kind of people that are having babies and make sure the resources match."
A community midwife team leader in Norfolk, Diane Riches, highlighted language difficulties as a particular issue when dealing with foreign-born mothers.
She told BBC Radio 5 Live that the increasing cost of interpreters was putting a strain on resources.
"We're finding that in the delivery room especially, women once they're in labour they're in pain, they're frightened, you often revert back to your own language and culture when you're frightened and so use of interpreters becomes very important and they're difficult to access because you can't predict what day any woman will go into labour."