Tail-End Brown Bleeding (TEB)

Tail-End Brown Bleeding (TEB) is brown or black spotting for two or more days at the end of a period.¹

TEB appears after the heavier days of bleeding have passed. Women who chart with the Creighton Model record it as a sign on the chart. Brown blood is older blood. It has taken longer to leave the uterus. In a healthy cycle, the endometrium, the lining of the uterus, sheds cleanly and the period ends. When the lining does not shed cleanly, TEB can appear. The Creighton Model records this pattern on a standard chart. The standard chart helps distinguish TEB from normal changes between periods.

The key question is why the lining did not clear on time. One possible cause is luteal phase deficiency, low progesterone after ovulation.²³ Another is chronic endometritis, a long-term inflammation of the uterine lining.⁴ Endometriosis, uterine polyps, and fibroids can also play a role. Each of these conditions can be identified and treated.

Many women regard TEB as normal. They have lived with it for years, and no one flagged it. As a result, a chance to find the cause is missed. A fertility chart shows the clinician a pattern across many cycles. A single symptom report cannot show that pattern. One brown day at the end of a period means little. Two or more days, cycle after cycle, is a signal that warrants evaluation.

TEB points toward a cause without naming it. It shows the clinician where to look. NaProTechnology-trained clinicians interpret TEB alongside other chart signs and hormone tests timed to the cycle. Together, these findings help identify the condition behind the pattern. The goal is to find and treat that cause.