A visibly pregnant woman was shoved out of a car and found dead on a Brooklyn street early Wednesday — and authorities are questioning her boyfriend, according to police sources.

Investigators are also probing whether the boyfriend was responsible for dumping their 2-year-old son on a Queens street, where the tot was found safe but alone, sources told The Post.

Mom-to-be Tatiana Walton, 27, was found lying unresponsive on Lorraine Street, outside her home in the Red Hook Houses, just after 2 a.m., and pronounced dead at New York Presbyterian-Methodist Hospital, according to cops and sources. It was unclear whether she was dead before or after the shove.

A witness told cops that shortly before the expectant mother was found, they saw a car resembling that of Walton’s boyfriend pull up outside the Lorraine Street residence, according to sources.

A man hopped out of the car, ran inside the building, emerged a short time later, and drove off — but not before shoving Walton out of the car and onto the street, sources said.

Investigators broke the news to Walton’s relatives, who inquired about the whereabouts of the 2-year-old son she had with the boyfriend, sources said, adding that the mom had an order of protection against the beau.

When cops found a male toddler all alone on 84th Street in Jackson Heights, Queens a short time later, investigators put two and two together and confirmed that the tot is the couple’s son, according to NYPD insiders.

The boy was in good health and is now in the custody of the city Administration for Children’s Services, sources said.

Meanwhile, cops in Suffolk County, Long Island caught up with Walton’s boyfriend, who was brought to Brooklyn for questioning.

He was not immediately charged with a crime, however, and The Post is withholding his name.

It was unclear whether he was the father of the unborn child as well.

The medical examiner will determine Walton’s cause of death.