Crowe told Australia's Nine Network, "It's a lot of fun and she's feeling all the effects of it."
Crowe and Spencer were married on his 39th birthday at his cattle property in northern New South Wales in April. He said his wife is 14 weeks pregnant.
Sky News noted that before his marriage, the New Zealand-born, Australian-raised actor developed a reputation as a hard-drinking, brawling star. Crowe has led a quieter life since his marriage and is currently touring Australia with his band Thirty Odd Foot of Grunts.
Crowe won the 2001 best actor Oscar for "Gladiator."