It turns out that your Fitbit can do more than let you know how far off your 10,000 daily steps you are.
One couple from New York found out they were expecting their first child through the fitness tracker.
The Reddit user, who only identifies himself as David, bought himself and his wife, Ivonne, Fitbits after they resolved to get in shape in the new year.
But when Ivonne's resting heart rate was consistently registering as high, he suspected a problem with the device.
"I thought was something was defective in the machine," David told Buzzfeed.
He posted to Reddit last week asking for advice.
"My wifes [sic] fitbit is showing her heartbeat being consistently high over the last few days," David posted to the online community. "2 days ago, a somewhat normal day, she logged 10 hours in the fat burning zone, which i would think to be impossible based on her activity level. Also her calories burned do seem accurate. I would imagine if she was in the the fat burning zone she would burn a ton of calories, so its not lining up.
"Im not sure if something is wrong with the sensor. is there a way to reset or recalibrate [sic] the device? Id like to try that before I contact customer service about a possible replacement."
Some users responded that recent updates of Fitbit's firmware made heart rate tracking "inconsistent".
Another user thought the firmware was fine.
"Has she experienced anything really stressful in the last few days or is it a possibility she is pregnant," asked Thatwasunpleasant.
Ivonne and David began trying for a baby several months ago and he replied that it was a "strong possibility".
The following day he updated the thread saying: "I'm going to be a dad!"
A normal resting heart rate for an adult is between 60 and 100 beats per minute, but during pregnancy the body works harder, meaning your heartbeat and breathing rate are faster.
"I never even knew that was a legitimate symptom," David said.
"We were both obviously very surprised, very happy. It's definitely a great story to tell [the baby] one day about how it happened, and [we are] happy to have all the support of people on Reddit."