Health chiefs have urged pregnant women to make sure they are immunised against whooping cough.
More than 200 cases have been reported across the Lothians since the start of the year.
The take-up of the whooping cough vaccination is high, but the number of cases is still rising, with 208 patients treated by NHS Lothian in 2012.
Dr Richard Othieno, consultant in public health medicine at NHS Lothian, said: “Immunisation is the safest and most effective way to protect children and our communities against serious diseases.
“Over the past year we have seen a significant increase in the number of confirmed cases whooping cough.
“We have written to pregnant women in Lothian to encourage them to be vaccinated.”