The Department of Health has approved a recommendation to consolidate all hospital births in the Northern Trust area at the Antrim Hospital site.
It said the decision had been taken to "ensure safe, consistent and sustainable care for mothers and babies in the trust area".
The recommendation was made by the Northern Trust Board following a 14-week public consultation.
In a statement, the Northern Trust said the change will come into effect from 17 July and "preparations are now underway to implement that decision".
Maternity services are currently provided from the trust's two acute hospitals, Antrim Area and Causeway, but concerns have been raised over the sustainability of services at the Causeway facility in Coleraine, where the number of births is lower.
The department also said there were difficulties in recruiting and retaining consultants at the Causeway maternity unit.
In a statement on Thursday, DOH Permanent Secretary Peter May said: "An overriding priority for our health service must be the provision of safe care for our population.
"This decision is in the best interests of mothers and babies in the Northern Trust area."
Mr May continued: "Maintaining the current service across both the Causeway and Antrim sites would not be sustainable.
"Avoiding planned change would simply lead to unplanned and forced change."
The service change relates only to births. Antenatal and postnatal clinics will be retained and enhanced on the Causeway site.
The department said the "unsustainability" of the current Causeway maternity unit relates to falling birth numbers at the hospital and associated difficulties of recruiting and retaining consultants and other staff.
It said the Causeway maternity unit has become reliant on locum and temporary staff, making the provision of consistent care more difficult.
A statement said: "Crucially, it has become increasingly challenging to maintain adequate consultant cover at the maternity unit - including consultant cover for the transfer of seriously ill babies to a neonatal unit with staff who are specialised and skilled in providing care for sick newborns."
Conditions of the consolidation of services at Antrim include making planned capacity changes at the hospital.
The Northern Trust will also be required to prioritise the development of an interim three-bedded Alongside Midwife Led Unit at Antrim.
Mr May said: "I have reviewed the trust's consultation outcome in line with the 2019 Department of Health Guidance Change or Withdrawal of Services - Guidance on Roles and Responsibilities.
"I have also received advice and assessment from the Department of Health's Strategic Planning and Performance Group and the Public Health Agency.
"I am satisfied that my decision is in accordance with Northern Ireland Executive Formation legislation and the associated guidance published by the Secretary of State for Northern Ireland.
"It is also consistent with the wider health transformation agenda which acknowledges that changes need to be made to ensure sustainability of services."
Welcoming the decision, the trust said: "We strongly believe this is the best outcome for women and babies in our care.
"It will allow us to continue providing the highest standard of inpatient maternity care and births at one, dedicated site, with a safer, more sustainable staffing model.
"Any women who are due to give birth at Causeway Hospital will be contacted directly by the Trust. We have also set up a helpline to answer any queries from women who are due to give birth at Causeway.
"We recognise this has also been an uncertain time for our very dedicated team of maternity staff at Causeway Hospital and we will be supporting them through this period of transition.
"Causeway Hospital is a key part of the Trust’s acute hospital network and we remain committed to maintaining acute services and an Emergency Department at the site.
"We recognise that the hospital and its staff play a vital role in serving the local community, and we want to enhance rather than diminish that role.
"Causeway Hospital will retain its high quality antenatal and postnatal care which we recognise are critical local services for women.
"We will also be enhancing these services so that pregnant women will have access to complex antenatal care and clinics at Causeway Hospital."
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