“It was also established that she was approximately eight months pregnant. Despite the efforts of paramedics, the victim sadly died at the scene.”Her baby was delivered at the scene before being taken to hospital. The child (we are not confirming gender at this stage) remains there in a critical condition.” Detective Chief Inspector Mick Norman, who is leading the investigation, said: “This is a horrific incident in which a young mother has lost her life and her child is critically ill.”Our sympathies go out to her devastated family; they are being supported by specially trained officers following this awful event, and I would ask that they are left alone at this time as they come to terms with the enormity of what has happened.”London mayor Sadiq Khan tweeted: “Violence against women is endemic in society and devastating murders in the home, like this one, show the scale of the problem we face.”My prayers are with this innocent child, and with the mother it has so tragically lost.”Neighbours said that three woman, one of whom was pregnant, lived at the house and they had a small dog.One neighbour said she had got up at about 3.30am to do her prayers when she heard a dog barking at the house, which is two doors down.The neighbour, who did not wish to be named, said she was “shocked and surprised” to hear about the attack.A police cordon was in place around the two-storey semi-detached house on Saturday night, with three uniformed officers stationed outside. A pregnant woman was killed and her unborn child left critically injured in a knife attack in South London.The 26-year-old victim, who was about a month from her due date, was found with fatal stab wounds at a home in Thornton Heath at about 3.30am on Saturday.Paramedics delivered her baby at the scene and took it to hospital, where it remains in critical condition.Police arrested a 37-year-old man on suspicion of murder following the attack.A 37-year-old man has been arrested on suspicion of murder and is in police custody, with the force stating officers “retain an open mind to any motive”.The Metropolitan Police said: “Police were called by London Ambulance Service (LAS) at 3.30am on Saturday June 29 to reports of a woman in cardiac arrest inside an address at Raymead Ave, Thornton Heath.”Officers attended along with the LAS and found the woman, aged 26, suffering from stab injuries. Lights could be seen inside the property, which is in a quiet one-way street off London Road near Croydon University Hospital.Anyone with information should contact police on the dedicated incident room number of 0208 721 4005, or ring 101 quoting CAD 1358/June 29. Alternatively, contact Crimestoppers on 0800 555 111. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.