How will Bernadette handle her outbursts as she experiences her gestation?
In "The Valentino Submergence, Howard and Bernie nurse a rabbit back to health that almost drowned in their hot tub looking very parental while doing it. After Howard heads to the emergency room, Bernadette tells the rabbit that she'll have to find another time to tell Howard that she's expecting. The rabbit didn't die, but that is a cliché for being pregnant.
In "The Positive Negative Reaction", she tells Howard the news. Howard is at first freaked out a the responsibility of raising a child and then embraces the future as much as Bernie does.