A.B.
Hi J.,
I would think this is probably ok as long as it isn't a concerning amount (soaking a liner for example). When you breastfeed, it causes uterine contractions which help the uterus to return to its original size. It would make sense that those contractions also help to expel any remaining afterbirth.
Of course, a quick call to your ob or midwive can help to put your mind at ease also - they will be more qualified to answer based on their knowledge of you and your ob history.
Congrats on your new little one!!