The first menstrual period after childbirth is particularly heavy.

The first menstrual period after childbirth, often referred to as the first normal menstrual cycle following "postpartum lochia," may differ from previous periods, especially in terms of flow. This is primarily due to the body's gradual return to normal hormone levels and the ongoing process of endometrial regeneration. Increased menstrual flow during the first cycle may occur because the endometrium has become thicker, requiring the expulsion of more tissue. In addition, breastfeeding can also affect the resumption and regularity of menstruation; women who breastfeed sometimes experience more irregular cycles or heavier bleeding. However, if the menstrual flow is excessively heavy to the extent of disrupting daily life—for example, requiring frequent pad changes or lasting longer than seven days—or is accompanied by severe pain, dizziness, fatigue, or other symptoms, this may indicate an abnormal condition. Possible causes could include poor uterine involution, endometriosis, hormonal imbalances, or other gynecological issues. In such cases, timely consultation with a doctor is recommended for examination and diagnosis of the underlying cause.