Air carrier First Officer reported a traffic conflict with a helicopter during approach. Flight crew momentarily leveled off; then continued the approach.

Narrative

DCA Converging Helicopter Traffic On Day 0 at XA:48; Fight ABCD was on the RNAV (RNP) Z Runway 19 into DCA when ATC issued a tra'c advisory for converging helicopter tra'c. At the time of the advisory; our aircraft was fully con'gured with speed reducing just abeam GREYZ on the approach. DCA Tower informed us that Tra'c was o' our left wing; 500 feet below" as we were descending making the turn between GREYZ and FONVI looking for the tra'c and converging on TCAS less than 2.0NM. I was FO (First Officer) (PF) from the right seat; I kept the Autopilot engaged as the Captain (PM) was looking for tra'c. As the helicopter closed in first TCAS alert was at 800 feet up until reaching 300 feet on the MFD (Multi-function Flight Display); I made the decision to temporarily level the aircraft using TCS (Touch Control Steering) at approximately 1200' AGL until the tra'c was behind us. The TCAS target after 300 feet had only showed an icon with no altitude and we were unable to see tra'c in sight. ATC then informed us that the tra'c was behind us so we decided to disengage Autopilot and TCS to descend back onto the approach glide path. We then continued a stable approach to land the aircraft safely. After reviewing ATC audio; we were informed about the initial location and altitude of the helicopter tra'c; although; we were not updated about the closure rate of the two aircraft nor their vertical separation. I would hope that our aircraft's TCAS would issue an RA if the closure rate became undesirable; but out of an abundance of caution; the decision was made to momentarily stop the decent until we were clear of con'ict. A lack of coordination; communication; and situational awareness created unnecessary risk just above 1;000 feet."