A mother awoke to find her toddler daughter dead beside her after the child had climbed under the duvet to be close to her, an inquest heard.
Sienna-Louise Burns-Hainesborough, aged 15 months, died from sudden childhood death syndrome, the coroner said.
The child's mother Kirsty Hainesborough, 24, got the whole family to sleep downstairs in Grimsby, Lincolnshire, because she was worried about some trouble in the street earlier in the day.
Happy family: Kirsty Hainesborough (right) holding her daughter Sienna Louise who died after after getting under the duvet as she slept. Her fiance Christopher Burns is holding their other child, Lily
Kirsty put Sienna and her sister Lily to sleep on one sofa with their father Christopher Burns, 30, while she slept on another, the inquest in Cleethorpes Town Hall was told.
But in the morning the distraught mother found Sienna's lifeless body at her feet under the duvet after the young child snuggled in with her during the night.
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The child's father Christopher said the family decided to sleep downstairs in the living room on January 5 last year after some troublemakers had come to the door.
He said he had fallen asleep on one sofa, with Sienna-Louise and her sister Lily sleeping at either end. Kirsty was asleep under a duvet on the other sofa.
Mother and child: Kirsty holds her daughter Sienna-Louise who died on January 6 last year
In the early hours of January 6, Christopher awoke and could not see Sienna-Louise at his side.
On checking the other sofa, he found her under a duvet at her mother's feet. Emergency services were called to the home but they were unable to revive the infant.
Both parents told the inquest they were aware of advice, given by health visitors, about the dangers of co-sleeping with children.
A post-mortem examination concluded the young girl died from sudden childhood death syndrome.
Detective Sergeant John Shepherd said the infant had made her own way from one sofa onto the sofa occupied by her mum.
Grimsby and North Lincolnshire Coroner Paul Kelly said: 'She made her own way to the sofa on which her mother was sleeping and burrowed her way under the bedclothes.'
He concluded the infant died from unexpected death in childhood in which accidental co-sleeping was a contributory factor.
WHAT IS SUDDEN UNEXPLAINED DEATH IN CHILDHOOD?
Sudden unexplained death in childhood (SUDC) is less common than sudden infant death. It's estimated to occur in 1.5 deaths per 100,000 live births.
By definition, the cause(s) of death in these children is unknown. SUDC generally occurs in children aged one to three, and more often in boys.
Factors that may increase the risk include a family history of seizures, a recent minor head trauma and/or a family history of sudden infant death syndrome or SUDC.
Most are found prone, often with their face straight down into the sleep surface.
The diagnosis of SUDC can be made only after thorough review of the medical history of the child and its family, microscopic evaluation of the scene where the child was found lifeless, and post-mortem examination.
For more information: www.sudc.org