Nick Viall and Natalie Joy have got babies on the brain.

And not just because they're in the trenches of raising one for the first time. As the Bachelor alum and his fiancé celebrated their daughter River Rose Viall turning 4 months this week, Natalie shared their plans to expand their family.

"[We are] absolutely not one and done," the 25-year-old told Page Six in comments posted June 7. "We both come from big families."

Natalie continued, "We actually had a pregnancy scare the other day and we both kinda, like, visualized for a split second what it would be like to have another and we were both like, 'Not right now. We cannot right now.' But then we were like, 'It would kind of be fun for River. She would have someone so close in age.'"

According to Natalie, she and Nick, 43, would likely try to conceive a second child after River reached certain developmental milestones. "I think we're definitely gonna wait a little bit longer," she said, "maybe for River to be able to talk or walk or something before we start trying for another."

And Natalie said the couple does not plan on stopping at two. "We definitely want three, four," she said, "as many as God will bless us with."

She made her comments weeks after she and Nick, who wed in April, went on a honeymoon in Puerto Rico with her mom and River. It marked their second attempt, as the couple originally planned to vacation in the Turks and Caicos Islands earlier in May but were stopped at customs upon their arrival at the airport due to a problem with Natalie's passport.

During their honeymoon in Puerto Rico, the couple enjoyed both family time and time alone. "We have an outdoor shower," Nick said on the May 16 episode of his podcast The Viall Files, "with a little bit of privacy. We did have sex."

See pics of the family on their honeymoon...