A pregnant US teen has been hit with a taser in New York despite pleading with an officer to stop.

Dailene Rosario, 17, was wrestled to the ground by a plain clothes NYPD sergeant before being tased on her side despite repeatedly screaming "I’m pregnant! I’m pregnant".

Police were called to an apartment complex in the Bronx on Friday evening after a report someone was having an asthma attack.

When they arrived they saw two men fighting on the fourth floor and called for backup.

Up to 10 police arrived at the apartment and tried to disband the crowd of people.

Dailene Rosario suffered burns to her side after being tased (Facebook)

Rosario suffered large burn marks to the side of her body.

Witness Danielle Lopez, 33, who was at the party was "disgusted" at the level of force police used to detain the 17-year-old, the NY Daily News reports.

"She was screaming it and we were screaming it, her mother was screaming it," Lopez said.

"She's four months pregnant. She has a belly. You can tell. I was disgusted."

NYDP officers are warned not to use their stun guns on children, the elderly or pregnant women.

Internal Affairs investigators interviewed witnesses following the incident however none of the arresting officers have been reprimanded.