CHULA VISTA, Calif. - A pregnant Guatemalan woman arrested on suspicion of crossing the border from Mexico without authorization gave birth a short time later at a U.S. Border Patrol station in Southern California, authorities said.

The 27-year-old woman and her family were spotted walking just east of the Otay Mesa Port of Entry near San Diego on Sunday, the Union-Tribune reported. It is believed they used a ladder to get over the border fence, said Border Patrol spokesman Jarrett Decker.

The agent who made the arrest noticed the woman was pregnant but said she did not appear to be in distress and did not request any medical attention, officials said.

Once they got to the Chula Vista station, the woman, the baby’s father and two children were being examined for a routine medical assessment when she went into labour, officials said.

“The medical staff, along with agents, prepared an area for the mother to give birth,” the Border Patrol said in a statement.

The woman and her baby girl were taken to a hospital and were in stable condition, the newspaper said Wednesday.

“Our agents are well trained to manage the unexpected, and I’m proud of the work they did in caring for this mother,“ Chief Patrol Agent Aaron Heitke said in a statement.