The Mercedes motorsport boss confirmed the news in the paddock at Austin, telling reporters: "Yes, it's true".
"My wife Susie is pregnant and we are expecting our baby in April," he revealed. "Whether it is a boy or a girl, the main thing is that it is healthy."
Susie Wolff, who previously raced in DTM, now serves as a pundit for Channel 4 in the UK, but she has missed a number of races recently and she will not be attending the United States or Mexico Grands Prix either.
Bahrain International Circuit - Winter testing