A San Francisco couple’s trip to the hospital turned into an unexpected roadside birth Saturday when gridlocked traffic left them stranded in Golden Gate Park.

Karollyn and her partner, Nate, were heading to the hospital through the park when vehicles came to a standstill on Crossover Drive near Martin Luther King Jr. Drive, the San Francisco Fire Department said.

As Karollyn’s labor progressed, Nate pulled onto the shoulder and called 911 shortly after 4:30 p.m.

Although an ambulance was sent to the scene, traffic was so backed up that paramedics left their vehicle several blocks away and continued on foot.

Help arrived from an unexpected source: A doula caught in the same traffic noticed what was happening and stepped in to guide Karollyn through the delivery before emergency crews could reach the couple, The San Francisco Standard reported.

Karollyn and Nate welcomed a healthy baby girl, Cielle Ray, just before paramedics arrived, according to the outlet.

“We were so fortunate to have the support that we did, especially some medical professionals that were sitting in the same traffic,” the family said in a statement provided through ambulance company American Medical Response. “Most notably, a doula that helped coach Karollyn through the process until the paramedics arrived.”

Fire Engine 14 arrived soon afterward, SFFD spokesperson Capt. Jonathan Baxter said.

The traffic congestion was particularly intense because Caltrans had closed part of Highway 101 for resurfacing, diverting motorists toward 19th Avenue, Park Presidio and nearby roads.

A collision involving multiple vehicles on 19th Avenue further worsened the backup along the southern edge of the park.

The couple said they had occasionally joked that their baby might arrive in the car, but never expected that scenario to become reality.

“We took a route that I take every morning to work without issues,” Nate said, according to AMR, “and just so happens that the day with the worst traffic is the last day we needed it.”