Irregular periods – what's still normal and when should you get checked?

What is a regular cycle?

A regular menstrual cycle means that the time between two bleeds remains roughly consistent over several months. Cycle lengths between about 21 and 35 days are considered typical. What matters most is not a specific number, but rather the recognisable rhythm of your own body.

Small variations of a few days are completely normal and no cause for concern. It is only when the gaps between bleeds vary significantly, bleeds become very infrequent, or stop altogether for an extended period, that closer attention is warranted.

Irregular periods – what does that mean?

We talk about an irregular cycle when any of the following patterns appear repeatedly:

• The gaps between bleeds vary considerably.
• Your period is absent for several months.
• Bleeds occur very frequently or are unusually heavy.
• Spotting or intermenstrual bleeding occurs – that is, bleeding outside of your regular period.
• Your cycle changes noticeably without an obvious reason.

These changes do not automatically point to something serious. However, they deserve attention – especially when they appear for the first time or persist over a longer period.

Common causes of cycle changes

Hormonal shifts in certain life phases

In some phases of life, the hormonal balance changes quite naturally. This includes the first years after the first menstrual bleed, the period following pregnancy and breastfeeding, and the perimenopause – the phase leading up to and into the menopause. During perimenopause in particular, many women experience shorter or longer cycles, irregular bleeds, or temporary gaps. This is often a normal part of hormonal transition, but it should be monitored so that other causes are not overlooked. You can find more information in our section on menopause consultation.

Stress, lack of sleep and emotional strain

Prolonged stress or significant physical and emotional strain can have a noticeable impact on your cycle. The body responds by shifting ovulation or suppressing it temporarily. These changes are often reversible once the stressful period eases.

Body weight, nutrition and exercise

Significant changes in body weight, highly restrictive eating patterns, or intensive physical training can all influence hormonal processes – both at low and at high body weight. Not every change leads to cycle irregularities, but when disruptions persist, this connection is worth considering.

Hormonal causes

Among the more common medical causes are thyroid disorders, elevated androgen levels (male hormones), and polycystic ovary syndrome – PCOS for short, a hormonal condition in which ovulation is irregular or absent. When cycle irregularities are persistent or pronounced, medical evaluation is advisable. You can read more about this on our PCOS treatment page.

Structural changes in the uterus or ovaries

Cycle changes can also arise from structural causes. Benign conditions such as cysts, polyps, or fibroids – benign growths in the uterine muscle – are frequent contributors. More rarely, other changes in the uterus or ovaries may trigger bleeding irregularities. This is why investigation is important when bleeding changes noticeably or occurs for the first time – particularly at an older age or after menopause.

When waiting makes sense

Not every change in your cycle requires immediate medical investigation. A watchful waiting approach can be appropriate when:

• there is a clearly identifiable trigger, such as an acute illness, travel, or a particularly stressful period,
• the change is only temporary,
• there are no additional symptoms,
• your period returns on its own within three to four months at most.

During phases of hormonal transition, your cycle may simply need time to adjust. That is not a sign that something has gone wrong – it is the body's way of finding its new balance.

When to see a doctor

Medical evaluation is recommended when:

• your period has been absent for more than three to four months,
• bleeds are very frequent, very heavy, or unusually painful,
• spotting or intermenstrual bleeding occurs,
• your cycle changes suddenly and significantly without an obvious cause,
• bleeding occurs after menopause – this always requires evaluation.

The aim is not to alarm, but to provide clarity and reassurance. Changes like these can be discussed and assessed together in our hormone consultation.

What examinations may be useful

Which examinations are needed depends entirely on your individual situation. In many cases, the conversation itself comes first – followed by an ultrasound scan, which can already provide important information.

Blood tests are not always necessary. Hormone levels fluctuate considerably throughout the cycle and even from day to day. They do not always reflect the underlying cause of a cycle irregularity. Whether hormone testing makes sense depends, among other things, on the phase of the cycle, the pattern of irregularity, and the symptoms present. That is why we decide individually which investigations are appropriate in each case.

Extended diagnostics without a medical indication are generally not covered by statutory health insurance and may be carried out as a self-funded service. Before any self-funded examination, we discuss the benefits, limitations, and costs with you transparently.

Why regular bleeding matters

When bleeds become very infrequent or stop altogether over a longer period, the uterine lining can build up continuously without the regular shedding that a bleed provides. Over time, this is not favourable for the health of the uterine lining.

As a rough guide: a bleed should occur at least every three to four months – either spontaneously, or with targeted support if that is medically appropriate. The goal is not a perfect 28-day cycle, but the protection of the uterine lining. This is something we can address as part of your regular gynaecological care when needed.

If you are wondering whether your cycle changes should be evaluated – please do get in touch. Together, we will find the right next step.

Elisa Mahlberg

References

• Deutsche Gesellschaft für Gynäkologie und Geburtshilfe (DGGG): S2k-Leitlinie „Diagnostik und Therapie von Blutungsstörungen