there two cases of bleeding which one may experience when taking microlut as stated in exact words at
http://www.old.health.gov.il/units/pharmacy/trufot/alonim/4259.pdf
Menstrual bleeding
Menstrual bleeding occurs at normal intervals and is of normal duration and intensity
in the majority of cases. However, both shortened and lengthened intervals are
observed.
For this reason the possibility of such changes in menstrual rhythm should, as a
precaution, be pointed out to the patient before the start of tablet taking. The changes
occur mainly during the first few months of use, but with continuing treatment the
cycle pattern tends to stabilize, and in most cases an individual pattern is
established. The patient should be encouraged to keep a record of bleeding on the
calendar contained in each pack.
• Procedure in the event of intermenstrual bleeding
Intermenstrual bleeding of varying intensity may occur, particularly during the first few
months. It is not a medical reason to stop tablet taking, as long as organic causes for
such bleeding can be ruled out by means of adequate diagnostic measures.
It is inadvisable to attempt to influence cycle disturbances by the additional
administration of an estrogen. This would only serve to reverse the changes brought
about by Microlut in the cervical mucus, thereby considerably jeopardizing the
contraceptive effect.