Letters have been sent to more than 700 mothers after it was discovered that a member of staff that used to work at a Kent hospital had Hepatitis C.
The trust said the risk of infection was very low
Women who gave birth at the Medway Maritime Hospital between 1994 and 2000 are now being offered blood tests.
Medway NHS Trust said the patients had come into contact with an obstetrics and gynaecology health worker who was diagnosed with the virus in 2002.
It has stressed that the risk of infection is very low.
Kathy Gillham, who was contacted by the NHS Trust, said: "The letter came and it was a total shock. You don't expect to go into hospital and contract a virus like hepatitis C.
"I was deemed as a low risk patient although I had a caesarean section, which is a major operation, so I think the screening should have taken place sooner."
A spokesperson for Kent Health Protection Agency said: "Patients who are notified will have the opportunity to contact a helpline and to receive counselling and a hepatitis C test. "The risk of infection is very small and the screening is being offered by the NHS as a precautionary measure."
Anyone who thinks they may have been affected has been urged to contact NHS Direct.