CHICAGO (CBS) — The CTA has a special delivery for expectant mothers: new “baby on board” buttons.

It’s the CTA’s way of encouraging riders to show courtesy to pregnant women riding trains and buses.

The blue buttons – which feature the message “Baby on Board! Could we please sit down?” – are designed to let riders know when a woman is expecting, and kindly ask them to give up their seat so the woman can sit down.

The CTA said not all pregnancies are easily spotted just by looking at someone, and they hope the buttons will make it easier for mothers-to-be to get a seat.

“CTA is always seeking out ways to promote a courteous and welcoming environment for all customers,” said CTA President Dorval R. Carter, Jr. “These new buttons are the latest effort toward that goal, and we hope they help foster courtesy and consideration among all customers.”

The buttons are available for free at CTA headquarters at 567 W. Lake St., on the CTA’s website at transitchicago.com/babyonboard, or at one of several hospitals; Northwestern Medicine Prentice Women’s Hospital, Rush University Medical Center, John H. Stroger, Jr. Hospital of Cook County, and Saint Anthony Hospital.