Ritual purity (wduhu and ghusl) are very effective on the child's upbringing and education and it is better or the mother not to breastfeed her child whilst she is in the state of ritual impurity (janabat). Also, there is no problem in having sexual intercourse with one's spouse in a room in which there is a child, if the child is not discerning (mumayyiz) between good and bad. However, if the child is awake, having sexual intercourse close to it is abominable and disapproved (makrooh).
In short, it’s better to breastfeed after ghusl