Herbs should be avoided during pregnancy.
During delivery, gynae will do blood transfusion if you have excessive bleeding.
However if you are worrying about the lochia (postpartum bleeding), some claim that raspberry leaf tea will help. However, you should consult your own doctor before taking any herbs especially during breastfeeding. http://www.livestrong.com/article/500803-does-red-raspberry-leaf-tea-help-postpartum-bleeding/