London, Jul 17 (IANS): Babies born outside normal working hours are at an increased risk of dying due to the absence of senior clinic staff in the wards.

Researchers studied one million births over 20 years and found that those born outside the normal nine to five Monday to Friday working hours were 70 percent more likely to die and the main cause of death was lack of oxygen, which can be due to the absence of senior clinical staff to spot the problem and react quickly.

The research also found patients were more likely to die if they were admitted to hospital at weekends.

Even when planned caesarean sections were excluded (which have a very low risk of death from lack of oxygen), there was still a 45 percent increased risk of death due to lack of oxygen when the baby was born out of hours.

One in four babies who died due to lack of oxygen had been born outside normal hours.

"For example, it could be explained by variation in staffing at different times of the day, such as the total number of staff or the profile of staff, in particular the immediate availability of senior clinicians," telegraph.co.uk quoted Gordon Smith, a professor in obstetrics and gynaecology, as saying.

"Improving the level of clinical care for women delivered out of normal working hours might reduce overall rates of perinatal death," he said.