A natural contraceptive method that inhibits ovulation is 

Lactational amenorrhea method is based on the fact that ovulation and therefore the reproductive cycles do not occur during the period of intense lactation following parturition. During periods of intense lactation, prolactin inhibits secretion of GnRH and thereby LH and hence ovulation does not occur.

Ovulation is not inhibited in coitus interruptus, periodic or complete abstinence.