Maternity staffing in Neath Port Talbot hospital has "deteriorated" resulting in the centre to shut for a week.
The decision comes into force from September 16 to 22, adding onto the current suspension of the homebirth service.
It follows pressures on the maternity services with staff members being affected with Covid-19 or having to self-isolate.
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Officials said the decision was made "to maintain and ensure safe maternity care for all our families, in line with professional guidance from the Royal College of Midwives and Obstetricians and Gynaecologists".
Midwifery led birth services will still continue in Singleton Hospital's Bay Birth Centre.
Families with planned births in the Neath Port Talbot area are being urged to contact with their community midwife to discuss the alternative options available.
A spokesman said: "We appreciate this may cause disappointment but please be assured the decision to suspend services has not been taken lightly.
"We would ask you make contact with us as soon as you have any signs of labour, which will help us plan your care.
"Where you are not in labour and it is safe to do so you will be advised to return home and wait for you labour to progress. This will minimise the amount of time you are separated from your essential support.
"We apologise for any disappointment this may cause and thank our community for the ongoing support at this challenging time."
It is not the only hospital unit in Wales which has been forced to close because of staffing issues.
Earlier this month it was announced that the minor injury unit (MIU) at Ysbyty Cwm Cynon, near Mountain Ash would stay shut "until furter notice".
And in Powys the MIU at Ystradgynlais Community Hospital also had to shut because of staff shortages.
New data published on Thursday, September 16, revealed there were 2,891 new positive cases across Wales, bringing the total number since the pandemic began to 317,481.
And the local authority with the highest infection rate in Wales is now Neath Port Talbot with 711 cases per 100,000 population over seven days.
Speaking at the Welsh Government press conference on Friday, September 10, the First Minister said there was tricky period ahead for the NHS as the virus continues to spread rapidly in Wales.
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