West Midlands Police has launched an investigation after the incident, which took place at a house on Whitebeam Road in Chelmsley Wood.
Three masked men armed with screwdrivers and a machete smashed a window and forced their way into the address at around 9.40pm on Friday threatening and assaulting the 43-year-old woman before running off.
Although the investigation is in the early stages, detectives believe the property was targeted in error.
The force said the area had been searched and house-to-house enquiries were being conducted, with high visibility patrols stepped up in the area to reassure the local community.
Detective Inspector Nicholas Barnes, said: "This was a cowardly crime, carried out on a family home, where people have every right to feel safe.
"I want to reassure people that incidents like this are very rare and we are doing everything we can to establish the full circumstances surrounding this incident to trace and arrest the people responsible.
"I would urge anyone who saw anything suspicious near to the property last night, or has any other information which could help us to get in touch.
"No matter how trivial you think that information is, it could prove vital to the investigation."
Anyone with information about what happened can get in touch via live chat at www.west-midlands.police.uk from 8am to midnight or by calling 101 anytime.
Anyone wishing to remain anonymous can call Crimestoppers on 0800 555 111, quoting crime number 20SH/48814Z/21.