There is a serious shortage of nurses providing neonatal care, MPs have said.
The Commons public accounts committee found that each of the 178 neonatal units in England had to close its doors once a week on average during 2006/07.
In a report published on Tuesday, the MPs found there were three vacancies per unit for qualified nurses.
The report also said one-third of units operated above the recommended occupancy rate of 70 per cent.
It warned: "High occupancy rates could have major implications for patient safety due to increased risk of infection or inadequate staffing levels."
The committee found that a 2003 decision to reorganise the country's units into 23 geographical networks had delivered some benefits, but two - the Northern and Essex networks - had yet to be formally established.
It also found that almost three-quarters of units had experienced delays in transporting babies because only half of networks could provide specialist transport services at all times.
Chairman Edward Leigh said: "There was widespread support for the reorganisation of neonatal services five years ago, resulting in the creation of 23 clinical networks.
"However, this change has had limited effect in reducing regional variations in mortality rates of babies born prematurely or suffering an illness needing specialist care.
"There are complex combinations of factors at work here, and primary care trusts need to improve their understanding of the high risk groups in their local populations.
"Constraints in capacity mean that the Department of Health is still struggling to meet the demand for neonatal services, which has risen year-on-year."
Leigh said the decision to establish a Neonatal Task Force was an "important development".
"It should set clear objectives and associated milestones for improving services to those who can really be described as the most vulnerable members of society".
