NBC’s “The Baby Borrowers” got a strong start earlier this year despite controversy over its premise. But by the time the show ended last night, it seems that interest had waned.

“Borrowers” posted a 2.1 adults 18-49 rating in the 9 p.m. slot, according to Nielsen overnights, off 19 percent from the 2.6 it had been averaging.

The show nearly tied last week’s season-low 2.0 rating, though it did place second in the timeslot behind Fox’s “So You Think You Can Dance,” against minimal competition.

“Borrowers” took a group of teenage couples and forced them to care for children in different stages of life, from infants to teenagers.

Last night’s segment threw them a twist. The couples cared for elderly adults, finishing out what NBC billed as a social experiment but many critics decried as cheap ratings-mongering.

The show premiered with a 2.8 rating last month, one of the better debuts of the summer.

Fox was first for the night among viewers 18-49 with a 2.2 average overnight rating and a 7 share. ABC, CBS and Univision all tied for second at 1.6/5, with NBC fifth at 1.5/5 and CW sixth at 0.3/1.
 
Univision began the night in the lead with a 1.8 at 8 p.m. for “Al Diablo con los Guapos,” while Fox and CBS tied for second at 1.5, Fox for a repeat of “Dance” and CBS for “Greatest American Dog.” NBC and ABC tied for fourth at 1.4, NBC for an “America’s Got Talent” rerun and ABC for a repeat of “Wife Swap,” with CW sixth with a 0.3 for a repeat of “America’s Next Top Model.”
 
At 9 p.m. Fox took the lead with a 2.9 for a new “Dance,” followed by NBC with a 2.1 for “Borrowers.” Univision was third with a 1.8 for “Fuego en la Sangre,” CBS fourth with a 1.7 for a repeat of “Criminal Minds,” ABC fifth with a 1.4 for a “Supernanny” rerun and CW sixth with a 0.3 for a rerun of “The Pussycat Dolls Present: Girlicious.”
 
ABC moved into the lead at 10 p.m. with a 1.9 for “Primetime,” with CBS second with a 1.7 for a repeat of “CSI: NY.” NBC and Univision tied for third that hour at 1.2, NBC for a repeat of “Law & Order” and Univision for “Don Francisco Presenta.”
 
Among households, CBS led the night with a 5.0 average overnight rating and a 9 share. Fox was second at 4.3/7, ABC and NBC tied for third at 3.3/5, Univision was fifth at 1.9/3 and CW sixth at 0.6/1.