The Police Service of Northern Ireland (PSNI) has named her as Sarah Montgomery, 27, a mother of two.
A 28-year-old man has been arrested on suspicion of murder and remains in police custody.
Detective Chief Inspector Tom Phillips said that police received a report at about 2.15pm on Saturday of an unconscious woman with a serious injury inside a house in the Elmfield Walk area of Donaghadee.
“Officers attended, alongside colleagues from the Northern Ireland Ambulance Service, who provided medical treatment at the scene,” he added.
He said the woman, who was also pregnant, was pronounced dead at the scene.
“Inquiries are at an early stage into this deeply tragic case. Our thoughts are also with Sarah’s family during this incredibly difficult time as they struggle to come to terms with what has happened,” Mr Phillips added.
“Sarah’s family are being supported by specially trained officers as the investigation continues.”
North Area Chief Inspector Yvonne McManus added: “We understand this news will cause shock and concern within the community.
“Local people will see our officers in and around the area, with cordons still in place today.
“Should anyone have any concerns or want to ask for help or advice, please speak to us. We want to help.
“We recognise the profound impact that violence against women and girls has on individuals, families and wider society.
“Addressing this issue remains a key priority, and we are committed to engaging directly with the local community to offer support, build trust, and help people feel safe.
“I am appealing to anyone who believes they may have information which could assist us with our investigation to contact us on 101.”
Northern Ireland’s First Minister Michelle O’Neill said: “My thoughts are with the family and loved ones of Sarah Montgomery as we learn of the heartbreaking news from Donaghadee.
“A young woman with her whole life ahead of her, taken in the most devastating way. Another family left shattered. Two children left without their mummy.
“Ending violence against women and girls must be a priority for every single person right across our society.
“We all have a role to play in ending the scourge of misogyny and violence.”
Deputy First Minister Emma Little Pengelly said: “My heart goes out to Sarah’s wee children, her family and friends and all who knew her.
“My heart breaks for Sarah. Just horrifying – another woman murdered.
“We know the work to tackle violence against women and girls will require a long-term approach, but I am so angry at every single murder and act of violence. It must stop.”
