The couple is said to be 'happy and overjoyed' about her pregnancy, reported Us magazine.
"They've been trying and waiting for such a long time," a source said.
Nick, 35, and Lauren tied the knot on April 12, 2014 at the Bacara Resort in Santa Barbara, California.
Their relationship and road to the altar was documented on VH1's reality show "I Heart Nick Carter", which aired in 2014.