hi thanks for writing to us
whenever there is missed periods first that has to be ruled out is pregnancy
pregnancy can occur in places other than
uterus like fallopian tubes
it is always advised to do pregnancy test
there could be abdominal infection
pelvic inflammatory disease can also abdominal cramps...foul smelling discharge
do a urine pregnancy test
if not planning for pregnancy try to follow a method of contraception
condoms prevents sexually transmitted diseases
hope this information was useful