How effective is the mini pill when breastfeeding?

Fairly. If you are 100% breastfeeding then the minipill is fairly effective especially in the first 6 mo after delivery. Later and once you start feeding the infant other foods it becomes less effective.

Related Questions

I'm on the mini pill and missed a pill and now have brown spotting. Cold this be implantation? I'm breastfeeding I'm 8 month old.

Maybe missed pill. Continue using your pills and use an alternate form of birth control. Check a pregnancy test in 1-2 weeks. Follow up with with doctor. All the best. Read more...
Not implantation. The brown bleeding is from missing the pill that given day with resultant withdrawal bleeding. Read more...

Started to take the mini pill as I'm breastfeeding. Now my period has stopped. Took test... Not pregnant. Is it normal?

Yes. Because the minipill contains only progesterone, it will not regulate the cycle - but it may suppress the cycle. Many women will not have bleeding or periods at all while taking the "mini pill". Other women will have irregular, unpredictable spotting or bleeding while taking that pill. Read more...