A prolactin of more than 90 μg/L is generally not serious if it is due to physiologic factors such as pregnancy and lactation. If it is caused by diseases such as pituitary prolactinoma or primary hypothyroidism, and treatment is not timely, it is more serious. To determine whether prolactin 90+ μg/L is serious or not depends on the actual condition and cannot be generalized. If prolactin 90+ μg/L is caused by physiological factors, such as pregnancy or breastfeeding, it is generally not serious and is normal, so there is no need to worry too much. If prolactin 90+ μg/L is caused by diseases, such as pituitary prolactinoma, primary hypothyroidism, etc., the prognosis is usually good after timely treatment, but if the treatment is not timely, it is relatively serious. To summarize, patients with prolactin more than 90μg/L need to undergo further relevant examinations to clarify the specific cause, and if necessary, need to cooperate with the doctor for active treatment.