For seven years, East Kent Hospitals Trust maintained the size of Louise Dempster's baby was to blame.
"It was just continuous lies," the 34-year-old told BBC News.
East Kent Hospitals chief executive Tracy Fletcher promised "to ensure lessons are learned".
Louise Dempster gave birth in May 2015 but the surgeon's error only emerged during an inquiry into poor maternity care at East Kent Hospitals Trust which reported this year.
It was Louise's first pregnancy and had been uneventful, until she developed two potentially dangerous conditions in the days before she was due to give birth.
A scan showed excessive growth of her baby, and that Louise had pre-eclampsia and a liver condition, which put her at risk of bleeding after birth.
She went into her local hospital, The Queen Elizabeth the Queen Mother in Margate, part of the East Kent Hospitals Trust, to be induced.
In October, an inquiry by Dr Bill Kirkup found at least 45 babies who died at the Trust's maternity services between 2009 and 2020 could have survived with better treatment.
When Louise's labour stalled, she was taken for a Caesarean section and her son was born large and healthy.
Louise was left by staff in the recovery room with her family, but her mother, Linda, noticed she appeared to be losing consciousness: "I was talking to her and I just saw her drift away and her eyes roll back."
The 61-year-old lifted her daughter's sheets and found "blood from head to toe".
Linda is a senior nurse who has worked nationally on quality and infection control. It didn't require her level of expertise to realise her daughter was in serious trouble.
"I tried to pull the emergency buzzer… but it didn't work," she remembers.
Louise says she thought she was dying: "All I remember is my mum screaming for help. And her stroking my hair and telling me she loved me. I knew that something was wrong".
Louise was taken back to surgery. After her operation the surgeon told her the bleeding had happened because her uterus hadn't shrunk back to its normal size after birth.
He inserted an instrument called a Bakri balloon to stop the bleeding - but a few hours later Louise was rushed back to surgery after Linda again spotted she was still losing a lot of blood.
Her original surgeon called in another surgeon, a cancer specialist, to help. Louise needed an extensive blood transfusion, but eventually recovered after several days in hospital.
The family felt there must have been something wrong with Louise's treatment and set about getting all her documents together and speaking to the clinicians involved.
But they felt like they hit a brick wall. All the notes confirmed her original surgeon's version of events. The Trust didn't consider what happened to be a serious incident and the investigation stopped.
Louise says she was told she was lucky to have a baby, and she should just "get on with it".
But the psychological impact was significant: "I think my mental health has probably been affected by it. I also feel like I've never had the opportunity to have another baby, which I really wanted to. I have lots of triggers from that time and lots of flashbacks I have to deal with," she says.
In 2020 Louise and her mother gave evidence to the Kirkup inquiry.
A few weeks before the findings were made public, inquiry chairman, Dr Bill Kirkup, asked to meet them.
He said he had discovered a document that had not been disclosed to the family, which showed Louise's bleeding had been caused by a surgical error, not by the size of her son as they had been led to believe.
Louise was furious her suspicions about what happened to her had been confirmed.
"They had so many points, they could have told me what actually happened. And they didn't," she says. "I spent so much time after the birth, visiting professionals trying to find out what happened."
The Kirkup report found evidence of staff "omitting key details in accounts given to families as well as to official bodies" and "the effect... was to cover up the truth."
The Trust says it is determined to improve clinical practice and will review Louise's care.
Its chief executive Tracy Fletcher said: "We apologise unreservedly to Louise and her family for the mistakes in her care and for failing in our duty to explain what went wrong, which falls far short of the standards and compassion patients should expect and deserve."