A mother and her baby daughter being monitored by social services were dead for at least a week before their bodies were discovered, an inquest has heard.
Joanne Thomas, 27, was found in her bed alongside four-month-old Harper at their terraced home in Troedyrhiw, near Merthyr Tydfil, last July.
Concerns were raised weeks before when Ms Thomas failed to take Harper for her injections, the hearing was told.
A social worker tried to visit three times before their bodies were found.
Acting coroner Andrew Barkley heard how he also sent out letters and attempted to contact her family.
The bodies were formally identified via dental records and DNA testing – with a pathologist saying it was “impossible” to say who had died first.
Police ruled out foul play as well as discounting the possibility of carbon monoxide poisoning, after “slightly raised levels” were found in the blood of Ms Thomas, who was a smoker, and her baby.
The coroner was told Ms Thomas regularly complained of feeling unwell in the weeks leading up to her death and may have been vomiting blood.
The inquest at Aberdare, continues.