Singleton Hospital's neonatal unit closed after high demand
The neonatal unit at Singleton Hospital in Swansea has been temporarily closed to new admissions because it is full.
The closure has also affected the general maternity unit, and some high-risk mothers have been sent to hospitals in Bridgend and Cardiff.
Staff said safety of mothers and babies was the main concern when deciding where people should give birth.
Concerned pregnant women, or those who require midwifery or medical care, are asked to contact the hospital.
In a statement, Abertawe Bro Morgannwg University Health Board said: "We appreciate this does cause anxiety and would urge any pregnant women who are concerned, or require midwifery or medical care, to contact as usual the numbers they have been issued antenatally.
"The neonatal service does experience peaks and troughs, and we are currently monitoring the frequency of these peaks."