Usually it’s the wife who lets the husband know they’re pregnant — but in one New York couple’s case, the husband discovered it first, after he noticed his wife’s unusually high heart rate on her Fitbit tracker.

David Trinidad, 34, of the Bronx, turned to Reddit to ask the online community if the Fitbit tracker’s sensor might be faulty, and if anyone knew of a way to recalibrate it.

“Has she experienced anything really stressful in the last few days, or is it a possibility she is pregnant?” another user replied.

See also100 things for kids on LI

“Pregnancy is a strong possibility, didn’t know that would jack up the heart rate. I might be a dad, YIKES,” Trinidad replied, posting as YoungPTone.

And then, after Ivonne Trinidad, 32, took at-home pregnancy tests, David returned to post, “I’m going to be a dad!”

The couple left today for a previously planned vacation to Rome, which has now turned into an unexpected babymoon, said Anaida Trinidad, David’s mom, in a phone interview. David works helping people find jobs, and Ivonne is a guidance counselor at a high school in Brooklyn, Anaida said. They are taking advantage of her winter break from school to travel, she said.

advertisement | advertise on newsday

“Oh my God, I’m over the moon excited,” Anaida said about learning she’ll be having her first grandchild. “Very happy.”

David Trinidad has since updated the original post, writing, “The outpouring of love has been incredible! Thank you to everyone who took the time out to share in the joy with us. It’s crazy to see our story pop up on news sites all day long. We have let our family in on the news and they couldn’t be happier. We are still very early on in the process, but we did have our first doctor visit today and all is well. We’ve decided to share our progress with anyone who would like to join us. Please follow the journey on Instagram @babyfitbit and on twitter @babyfitbit.”

The baby is due in October.