(CNN) "Boy Meets World" star Danielle Fishel and her producing husband Jensen Karp have welcomed a baby boy, she announced on Instagram on Monday.

It is their first child.

Her baby was born a month early, Fishel revealed, and is still in the hospital growing strong.

"One week ago today, on 6/24 at 4:52am, Adler Lawrence Karp made his entrance into the world, 4 weeks early. My water broke on 6/20, one day before my work week directing at Raven's Home ended and my maternity leave began. I was hospitalized that night and put on magnesium sulfate because Adler was only 35 weeks old. Unfortunately, after doing an ultrasound, our amazing OB discovered fluid in his lungs that was not there during our last appointment only 10 days earlier - and thus we entered a nightmare we'll never forget," Fishel wrote.

She continued: "We still don't have Adler home with us because the deeply good doctors and nurses in the NICU are working diligently to find out why the fluid is there and determine the best way to get it out. This has been the most trying week and a half of mine and @jensenkarp's lives but we have gotten through it with the support of our incredible family and friends who have shown up for us in unexpected ways."

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