Thanks for the query.
Mini pill can lead to menstrual irregularity sometimes.
And few women can experience amenorrhea
for few months also.
But unlike combined hormonal pills, the safety period of progesterone
pills is less.
If you delay the intake of pills for more than 3 hours, the protection percentage decreases.
For more details : http://srsree.blogspot.com/2013/12/guidelines-for-usage-of-progesterone.html
So, once go for blood test
If test comes negative, the possibility of pregnancy is less.
Then after completion of that pack, you can start combined hormonal pills.