Will menstruation during lactation reduce milk supply?

Having a menstrual period during lactation generally does not cause a decrease in milk supply. Milk production and menstruation are largely independent of each other. However, factors such as inadequate postpartum nutrition, excessive maternal fatigue, depression, or irregular breastfeeding may easily lead to reduced milk production. Typically, after the puerperium, the endometrium and ovarian ovulation function gradually recover, and other bodily organs progressively return to their pre-pregnancy state; menstruation may then resume. Such physiological recovery usually supports, rather than hinders, lactation.