FOUR PEOPLE WERE INJURED, INCLUDING A PREGNANT WOMAN, IN AN ACCIDENT ON THE INTERSTATE LATE SATURDAY NIGHT.  NORTH PORT POLICE SAY 21 YEAR OLD RENE ESPINAL-DIAZ OF ORLANDO WAS NORTHBOUND NEAR MILE MARKER 183 JUST BEFORE MIDNIGHT WHEN SHE LOST CONTROL OF HER 2000 FORD F-150 PICK-UP.  THE TRUCK SLID INTO THE DIRT MEDIAN AND ROLLED SEVERAL TIMES BEFORE COMING TO REST ON ITS TIRES.  A THREE YEAR OLD BOY WAS IN A CAR SEAT BUT WAS STILL EJECTED FROM THE PICK-UP.  HE, ALONG WITH ESPINAL-DIAZ AND A PASSENGER, WERE TAKEN TO THE NORTH PORT EMERGENCY ROOM WITH MINOR INJURIES.  THE FRONT SEAT PASSENGER, 20 YEAR OLD CLAUDIA VALENZUELA, ALSO OF ORLANDO, WAS BAYFLITED TO BAYFRONT MEDICAL CENTER IN ST. PETERSBURG IN SERIOUS CONDITION.  SHE IS EIGHT MONTHS PREGNANT.  POLICE SAY CHARGES ARE PENDING THE COMPLETION OF THEIR INVESTIGATION.