{"id":28998,"date":"2026-09-24T00:09:21","date_gmt":"2026-09-23T22:09:21","guid":{"rendered":"https:\/\/www.badania-medyczne.pl\/?p=28998"},"modified":"2026-10-20T13:10:23","modified_gmt":"2026-10-20T11:10:23","slug":"irregular-periods-hormone-tests-and-cycle-days","status":"publish","type":"post","link":"https:\/\/www.badania-medyczne.pl\/en\/irregular-periods-hormone-tests-and-cycle-days\/","title":{"rendered":"Irregular periods: which hormone tests to have and on which day of your cycle"},"content":{"rendered":"

The menstrual cycle is one of the most sensitive indicators of a woman’s health. It responds to stress, sleep, body weight, thyroid function, prolactin and androgens. That is why cycle disturbances are rarely \u201cjust a gynaecological problem\u201d; more often, they signal that something is happening across the hormonal system. This article explains what counts as irregular periods, the most common causes and which blood tests help distinguish between them. Results should always be interpreted by a doctor; the aim of this article is to prepare you for that discussion. The result report is issued in Polish.<\/p>\n

What does an \u201cirregular cycle\u201d mean?<\/h2>\n

A normal cycle lasts from 21 to 35 days (counted from the first day of bleeding to the first day of the next period), and differences between cycles do not usually exceed 7\u20139 days. Cycles are considered irregular when they are shorter than 21 days or longer than 35 days, their length varies by more than about a week, bleeding occurs between periods, or periods stop for 3 months or longer (secondary amenorrhoea). Very heavy or very light bleeding and severe pain are separate issues.<\/p>\n

In the first 2 years after your first period and during perimenopause, irregularity is partly physiological. At other stages of life, a change that persists for several cycles needs investigating.<\/p>\n

The most common causes<\/h2>\n