The ad was scheduled to begin airing Monday in Philadelphia, Erie, Scranton and Altoona and focused on Santorum's Pennsylvania senatorial career and loss in 2006, the Pittsburgh Tribune-Review reported.
"We have done this out of deference to Senator Santorum's decision to suspend his campaign for personal family reasons," said Andrea Saul, a Romney spokeswoman. "We have instructed stations this morning to pull the current ad [as soon as possible] and until further notice."
Santorum said Friday his daughter Bella was hospitalized. Bella Santorum suffers from a rare genetic disorder called Trisomy 18, which is often fatal, the report said.
Rick Santorum suspended his campaign to spend time with his family Monday and is set to begin a campaign tour across Pennsylvania beginning in Bedford Tuesday.
Saul said TV stations will comply with the request as soon as they are technically able and the campaign has sent another ad to air in its place.