Surprise! Boy Meets World 's Danielle Fishel Reveals She Is Pregnant with Baby No. 2 on 40th Birthday

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Danielle Fishel has a birthday surprise!

The Boy Meets World alum marked her 40th birthday on Instagram Wednesday by revealing that she is pregnant, expecting her second baby with husband Jensen Karp, another son.

"F O R T Y! I've never been more excited or hopeful for the next decade of my life," she began her caption, shared alongside a smiling photo showing off her baby bump. "I had a beautiful childhood, teenage years I still dream about, my 20's were insane (and mostly miserable) and my 30's brought me lows and highs but eventually I leveled out to a place of security."

"Security in who I am, what I believe, and with whom I want to spend precious time," continued Fishel. "I couldn't be more grateful to enter my 40's with my amazing husband and son, excitedly expecting the arrival of baby boy #2. My birthday wish is for all of you to tell someone how much you love them and walk through today with more patience than you normally might."

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The pair, who tied the knot in November 2018, welcomed their first child together, son Adler Lawrence, in June 2019, one month before his due date. Adler was in the neonatal intensive care unit due to fluid build-up in his lungs for 21 days.

"Adler is bottle-fed because of the issue that he had, something called chylothorax. It's a leak in the lymphatic system," Fishel told PEOPLE in September of that year. "Unfortunately, my breast milk was creating fluid in his lungs, and we had to take him off of breast milk and put him on a specially formulated formula that doesn't use the lymphatic system."

Chylothorax caused baby Adler to be "rushed via ambulance" to Children's Hospital Los Angeles after staff at Providence Tarzana Medical Center, where he was born, noticed his lungs didn't seem to be healing themselves as they initially thought, which was something Fishel was told was common with the rare condition.

"That was obviously devastating for us. It was traumatizing," recalled the mom at the time. "We were not expecting that. The last thing we had heard was that it looks good, the fluid's going down. We expected to have this ultrasound done and be told there was no more fluid in his lungs."

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"We were trying to be as positive as possible, and letting each other know that we're okay," Fishel recalled of their newborn's health scare. "We were obviously both still thinking of the other one, and saying, 'Oh God, I hope he's okay,' and 'She's worried about me.' "

"In the long run, when we ended up at Children's Hospital and we saw the other things that children and parents are facing, we put it in perspective and we were just so happy to have Adler with us," Karp added. "For every first-time parent, it's an adjustment to know it wasn't ideal, but he's healthy and he's going to make it. We have the best doctors around us, etc. Those are the things you kind of ease into."