A pregnant 16-year-old was slashed in the back of the head when her boyfriend got into a dispute with some men at the Dominican Day Parade in Midtown this afternoon, authorities said.

The girl, who told cops she was a few weeks pregnant, was taken to Bellevue Hospital in stable condition, officials said.

The incident occurred at 4 p.m. at the corner of 47th Street and 7th Avenue, cops said.

It was unclear what sparked the fight.

Three people were busted — a 16-year-old and two 20-year-old men — in the attack, but charges against them were pending, authorities said.

At least a half-dozen people also were arrested for various incidents of disorderly conduct during the parade, authorities said.