A mother and her baby daughter, who were being monitored by social services, were dead for at least a week before their bodies were discovered at their home in Wales, an inquest has heard.
Joanne Thomas, 27, was found in her bed alongside four-month Harper at their terraced home in Troedyrhiw, near Merthyr Tydfil, Wales, last July.
The alarm had been raised weeks before when Thomas failed to take Harper for her injections, Aberdare Coroner's Court heard.
A social worker tried to visit Thomas three times before they were found.
The bodies were formally identified via dental records and DNA testing and a pathologist said it was "impossible" to say who had died first.
Police ruled out foul play and carbon monoxide poisoning after "slightly raised levels" were found in the blood of Thomas, who was a smoker, and her baby.
Coroner Andrew Barkley was told Thomas regularly complained of feeling unwell in the weeks leading up to her death and may have been vomiting blood.
The inquest continues.