TMZ has learned that the Long Island hospital where J.Lo will probably give birth to her twins is practicing "pink drills" -- code for thwarting a possible kidnapping.

Sources at North Shore Medical Center tell TMZ the hospital conducted a "Code Pink" drill last Friday -- "Code Pink" is code for locking down the hospital to prevent a kidnapping attempt.

A rep for North Shore confirmed that the pink drill did indeed go down, but said that the timing is just a coincidence, but that's not what our sources are saying.

For the lowdown, check out TMZ TV tonight for the full scoop. Check your local listings.