The National Audit Office has raised concerns over the capacity of NHS neonatal services, describing them as 'challenged'.

The report, Caring for Vulnerable Babies: the reorganisation of neonatal services in England, published yesterday, highlights severe shortages of neonatal nurses.

The NAO found that on average neonatal units had three nurse vacancies or a 9 per cent national vacancy rate. It also showed that only half of the units met the British Association of Perinatal Medicine standards of one nurse for every two babies in high dependency care. Only 24 per cent met the standard of one nurse per baby for those in intensive care.

Karen Taylor, NAO director of health value for money studies, admitted the report highlighted 'serious concerns' about the capacity of NHS neonatal units to provide the level of care needed for some sick babies.

'We found a number of examples of babies being cared for in lower levels of care cots than they actually need,' she said. She blamed the variations in staffing on the fact that the standards were recommended but not 'mandated'.

'Overall neonatal units are not meeting the BAPM minimum standards, and the higher the level of care a baby needs the more likely the units are not to be meeting these standards,' she said.

The report found that shortages in nursing staff coupled with a shortage of cots in the right place at the right level of care and a lack of widespread specialist 24-hour transport mean that improvements in neonatal services are being limited.

It also showed that nearly a third of neonatal units operated above the BAPM-recommended occupancy rate of 70 per cent and three units operated above 100 per cent in terms of staffing capacity.

Ms Taylor said 'care is not satisfactory' in neonatal services.

Public accounts committee chair Edward Leigh MP (Conservative) said: 'It is shocking to hear that the safety of ill and defenceless babies is being compromised by a significant shortage of nursing staff.

'Neonatal services are still far from being at a level where we can feel reassured that every mother with a premature or ill baby will be seen and treated at their time of most need.'

Neonatal network mortality rates

Five highest mortality rates (deaths per thousand)

Midlands South, 4.8

Midlands North, 4.3

North West London, 4.0

Cheshire and Merseyside, 3.6

Yorkshire, 3.5

Five lowest mortality rates

Surrey and Sussex, 1.8

Essex, 1.9

Beds and Herts, 2.2

Norfolk, Suffolk and Cambs, 2.2

Central South Coast, 2.3

Network average, 3.0