The normal range of prolactin in women after pregnancy is around 10-210 ng/ml. When testing prolactin values are also affected by a woman’s diet, mental state, and rest. After pregnancy, estrogen rises and prolactin levels are higher than when you are not pregnant. High levels of prolactin can promote breast development, promote the development of milk ducts and milk follicles, increase breast size, increase areola and nipple size, and deepen areola color, while preparing for breastfeeding after delivery. The increase of estrogen will inhibit the secretion of lactogen and inhibit the secretion of systolic hormone to avoid the phenomenon of uterine contraction. Once the level of lactogen is too high, it will induce the secretion of systolic hormone, which will easily lead to uterine contraction and will lead to miscarriage and premature delivery, and this aspect of lactogen alone is not enough to determine whether it will lead to miscarriage.