Babies will not be delivered at the Causeway Hospital in Coleraine at the peak of the coronavirus surge.
The move comes as part of a five-step plan agreed by the Health and Social Care (HSC) system to reconfigure children's and maternity services as increasing numbers of Covid-19 patients are expected.
It aims to free up 130 beds in acute hospitals to treat the sickest patients.
The change comes came after Belfast City Hospital's tower block became the north's first dedicated coronavirus centre ahead of a surge of patients needing intensive care.
The City will become a 230-bed critical care facility with other patients, including cancer patients, moved elsewhere.
Step one of the plan, which is due to be implemented in the coming days, will see the delivery of babies diverted from the Causeway Hospital in Coleraine.
Women booked there over the coming weeks will instead be transferred to Antrim or Altnagevlin. Antenatal and postnatal care will continue.
Maternity services in Daisy Hill, South West Acute, Craigavon, Altnagelvin, Antrim, the Ulster and the Royal Jubilee Maternity Hospital (RJMH) will continue.
This initial stage of the plan will also see inpatient paediatric wards being closed at the South West Acute Hospital (SWAH), Daisy Hill (DHH) and Causeway Hospitals.
The second step of the plan will see the paediatric inpatient ward at the Ulster Hospital close, while step three will see either Antrim or Craigavon Area Hospital close to paediatric inpatients.
Step four will see which of the former two which remained open closing.
Step five - planned for the "extreme surge" - will see only two inpatient units remaining open - the Royal Belfast Hospital for Sick Children and Altnagelvin in Londonderry.
Staff from those locations will be redeployed to support these units.
The department said there will be "daily monitoring and communication across the paediatric network" during the surge.
The statement concluded by advising parents and carers if their child is unwell to contact their GP in the first instance.
"If your child is very unwell you should bring them to your nearest Emergency Department, contacting the hospital ahead of arrival if they have respiratory symptoms."
The Royal College of Midwives (RCM) said the changes must be reversed once the pandemic is over.
Karen Murray, the RCM's Director for Northern Ireland, said staff providing maternity services must be consulted about the changes.
"Equally, it’s important to ensure that temporary changes are reversed as soon as possible once the immediate crisis has subsided," he said.
"These are exceptional times and it is unfortunately necessary to look at how we deliver all parts of the health service to ensure that we can provide care for those affected by this virus whilst continuing to provide safe maternity care to women and their babies."
