Seven babies and three mums have died in two Greater Manchester maternity units in just eight months – sparking an independent investigation.
Bosses at Royal Oldham and North Manchester General hospitals called in outside experts to review the departments in light of the 10 tragedies.
It is understood the deaths took place between December 2013 and July last year – with four babies and two mums dying at Oldham, and three babies and one mother dying at North Manchester.
Police are continuing to question two men and a woman arrested after the death of a seven-week-old baby boy from severe head injuries.
Greater Manchester Police said they were not in a position to name the baby, who lived in the Clarksfield area of Oldham.
The 23-year-old woman, thought to be the child's mother, and a 35-year-old man originally arrested on suspicion of assault were rearrested on suspicion of murder and conspiring to pervert the course of justice.
A 26-year-old man is also under arrest on suspicion of murder and conspiring to pervert the course of justice.
Detectives have been given more time to question three people on suspicion of murdering a seven week old baby boy.
A warrant for further detention was granted at 6.30pm last night giving police a further 30 hours to question two men and a woman from Oldham, whose believed to be the baby's mother.
A post mortem examination revealed the baby died of severe head injuries.