Angela Jenkinson's body was discovered in Barker End Road, Bradford. The unborn baby also died.
Police said Mrs Jenkinson, who had a four-year-old daughter, had been punched at least once in the face before being strangled. There was no indication of sexual assault.
Detective Superintendent Gary Haigh, leading the inquiry, said she lived alone with her daughter 100 yards from where her body was found. She worked as a checkout operator at a Kwiksave store near by.
Mrs Jenkinson had been reported missing overnight after going out at 10pm on Thursday, leaving her daughter with a neighbour. Police were alerted when she failed to arrive for work.
A post-mortem examination showed the cause of death as asphyxiation.
Det Supt Haigh said the motive for the killing was unknown but as a result of inquiries, a 30-year-old Bradford man would be questioned.Reuse content