Kahit common lang talaga ang light spotting after pap smear or cervical check, better i-confirm mo pa rin sa OB mo next visit or call the clinic kung worried ka, mas mapapahinga ka lang ng loob, lalo na at 31 weeks na kayo at may discharge pa. Siguro naman okay lang, pero it's always better safe than sorry, especially pag may unusual amount or kasabay ng cramping or other signs.