The family of a mother and her baby daughter found dead at their Merthyr Tydfil home nine months ago say they have not gained any closure after an open verdict was recorded at inquest.
Joanne Thomas, 27, was found in her bed alongside four-month-old Harper at their terraced home in Troedyrhiw last July.
An inquest heard they had been dead for at least a week before their bodies were discovered.
Aberdare Coroner's Court heard concerns had been raised weeks earlier after Miss Thomas failed to take Harper for her injections.
A social worker told acting coroner Andrew Barkley he tried to visit Miss Thomas on three occasions before their bodies were found, as well as sending out letters and attempting to contact her family.
The bodies were eventually formally identified via dental records and DNA testing - with a top pathologist said it was "impossible" to say who had died first.
Police later ruled out foul play as well as discounting the possibility of carbon monoxide poisoning - after "slightly raised levels" were found in the blood of smoker Miss Thomas' blood and her baby.
A coroner was told Miss Thomas regularly complained of feeling unwell in the weeks leading up to her death and may have been vomiting blood.
Mr Barkley said: "There remains real doubt as to the cause of death. I cannot be sure exactly."
Miss Thomas gave birth to Harper on February 13, 2013.
The inquests heard the child was later placed on the "at risk register" by Social Services because of a volatile relationship Miss Thomas was in at the time.
However, by the end of May she was removed from that list and placed on the lesser "children in need" scheme - which the court heard was a "voluntary" scheme.
Social worker Jamie Robins said this had been prompted by more stability in Miss Thomas' home life.
The changes had included her moving out of the Caerphilly County Borough area and into a two-bedroomed house, which was owned by a housing association, in Church Street, Troedyrhiw.
Her family were also positive about how Miss Thomas was starting to turn her life around.
She had been a model student as a youngster and achieved 12 straight As at GCSE. However, the inquest into her death was told she "went off the rails" following a "personal matter".
The coroner said he was aware of the details, but would not be going into detail on it at the public hearing.
Mr Robins had his last face-to-face meeting with Miss Thomas on May 22. The next, he said was to be in "four to six weeks".
However, he said he was contacted by her health visitor after Miss Thomas failed to turn up for a GP appointment.
Mr Robins told the hearing he sent a letter to Miss Thomas to contact him and also tried to call her.
However, he insisted he was not able to make contact by telephone because "she was required to change her mobile phone on a regular basis".
In early June, Miss Thomas complained of feeling unwell and had her mother Iris to stay and look after Harper. After starting to feel better, Iris returned home.
On June 10, Miss Thomas sent a text message to her health visitor saying she would be unable to attend a meeting with her. The inquest heard the text was the last time Miss Thomas had used her phone.
As the days went on, concerns began to mount after no-one had heard from Miss Thomas.
Social services said they had tried to contact her on a number of occasions - attempting three home visits by June 28.
However, her mother Iris said the first time she was contacted by social services about her daughter was on July 3.
However, Mr Robins insisted he had tried to contact "members of her family".
He also explained that the next scheduled visit was not for a few more weeks and a case of a "child in need" was not as serious as one who was on the "at risk register".
The inquest also heard that Miss Thomas would go seven to 10 days without speaking to her family.
However, concern gave way to alarm after a neighbour looked through Miss Thomas' front window and was alarmed by what he saw.
The police were then called and found Miss Thomas and her daughter's badly decomposed bodies inside.
Detectives also discovered her front door had been unlocked the whole time.
Inside the house, small amounts of blood were found on a stair-rail and in a saucepan at her bedside.
After ruling out any third-party involvement, detective inspector Tudor Thomas said findings from the post mortem suggested Miss Thomas may have vomited blood.
A toxicological analysis of her blood found small amounts of paracetamol and the anti-depressant fluoxetine.
A medical report also gave details of a heart scan - which looked into the possibility of whether she had the rare cardiac condition long QT syndrome.
Pathologist Dr Stephen Leadbetter said the results of the post-mortem failed to shed any light into precisely how mother and baby had died because of the advanced stages of the decaying process.
He added: "What can I say about the sequence of deaths or whether their causes were natural or unnatural?
"On a scientific basis I am sorry to say that I do not know the answers to those questions."
However, he said that Harper's nappy was not overly soiled - which discounted the theory the child had been alive for some time on her own after her mother's death.
Dr Leadbetter also said there was no evidence of any injuries to either mother or baby.
Mr Barkley acknowledged that while Miss Thomas had a history of depression, there was no evidence to suggest she had taken her own life.
Based on the evidence, he also said there were no suspicious circumstances and deemed social services' response "was appropriate".
Mr Barkley added he would not be making the recommendation for a report into the organisation's dealings with Miss Thomas.
After an open verdict was recorded, Miss Thomas' sister Rachel Lewis said her family had not gained any closure from the hearing.
She said: "We are still devastated at the death of Joanne and Harper. Joanne was a good mum who was starting to turn her life around. Things were going in the right direction and then she died in such a tragic way.
"We thought we would come here to her inquest and get answers which have plagued us for so long - but all we have been left with is more questions.
"There's no closure for us."