Barash, 33, played mobster Johnny Zacchara on the soap until April.
Storms, 29, plays fashion magazine staffer Maxie Jones, who is in labor this week on the daytime drama and expected to give birth at any moment.
"We're having a little girl in January," Barash told People.com about his real-life bride.
"It's been the most amazing couple of months of our lives," he said. "We kept things quiet because of everything that can go wrong during the first trimester. ... Kirsten did have a rocky [time] and we were in and out of the hospital."
He admitted the news was a bit of a surprise since Storms has battled endometriosis.
"We talked about wanting to have kids and Kirsten was told she could try hormone therapy. It was pretty bleak as far as the probability of her being able to get pregnant," Barash told People.com. "But then we got back from a trip to Amsterdam and discovered we were expecting. We calculated that we conceived the baby in ['GH' star] Tony Geary's guest room!"