The Cycle and Irregular Periods
Irregular periods: causes & what helps – gynaecologist Basel
FMH Gynecology
Board certified
SGGG
Member
Colposcopy diploma
Certified
DE · EN
Languages
Spalenvorstadt 3
4051 Basel
An irregular cycle is common – and in many cases harmless. It can be part of a life stage, related to contraception, or a sign of an easily treatable cause. Sometimes, however, there is something behind it that should be assessed.
A normal cycle lasts about 24 to 38 days and can vary by a few days from month to month. It is considered irregular if the intervals vary considerably, the period comes more often than every 24 or less often than every 38 days, stops entirely, or if spotting, intermenstrual or contact bleeding occurs. Bleeding after menopause (more than 12 months after the last period) is never normal.
Women of all ages can be affected. In the first years after the first period and during perimenopause, an irregular cycle is to be expected; in mid-life, a new irregularity should be assessed.
Key facts
At a glance.
- Not every irregular cycle is a problem – it is often explainable.
- Common causes: life stage, contraception, thyroid, PMOS (formerly PCOS), stress and weight.
- If the period stops, we first rule out pregnancy.
- Extensive hormone testing is usually unnecessary – we test in a targeted way.
- Bleeding after menopause is never normal and should always be assessed.
- Contact bleeding is usually harmless (ectropion), but should be checked once if it recurs.
Causes
Background and risk factors.
Common causes are
life stage (young years and perimenopause – intervals often become shorter first, then longer and more irregular), pregnancy and breastfeeding, hormonal contraception (hormonal IUD, minipill, implant, three-monthly injection), PMOS (formerly PCOS) with long cycles and sometimes increased body hair or skin changes, thyroid over- or underactivity, severe stress, marked under- or overweight, and intense competitive sport. Organic causes such as polyps, fibroids or changes in the uterine lining are mainly relevant with additional intermenstrual bleeding and are usually well identified on ultrasound.
Risk factors
- Young years after menarche and perimenopause
- Hormonal contraception (expected)
- PMOS (formerly PCOS)
- Thyroid dysfunction
- Severe stress, underweight, competitive sport
- Marked weight gain
Frequency
Cycle irregularities are among the most common reasons for a gynaecology visit.
What matters is context
what is expected, and what needs assessment?
Symptoms & findings
How does it present?
Typical symptoms
- Intervals vary considerably from month to month
- Very frequent (< 24 days) or very infrequent (> 38 days) bleeding
- Period stops
- Spotting or intermenstrual bleeding
Common incidental findings
- Bleeding after intercourse (contact bleeding) – usually harmless, often due to cervical ectropion
- Skin changes or increased body hair (suggestive of PMOS)
- Desire to have children with an irregular cycle
When is it detected?
Assess promptly – or seek emergency care for acute symptoms – for: bleeding after menopause (always), very heavy bleeding with large clots or circulatory problems, new or persistent intermenstrual bleeding, absent period with possible pregnancy, or if your usual pattern suddenly changes significantly.
Diagnostics
How the diagnosis is made.
The starting point is a conversation and the cycle history – a cycle chart or app helps identify the pattern. If the period stops, we first do a pregnancy test. Depending on the situation, this is followed by a gynaecological examination, an ultrasound of the uterus and ovaries (showing polyps, fibroids, the uterine lining and signs of PMOS), and targeted laboratory tests based on suspicion – for example TSH, prolactin or androgens. For contact bleeding, we add a chlamydia swab, especially in younger women.
Examinations
- Conversation and cycle chart
- Pregnancy test for absent period
- Gynaecological examination
- Transvaginal ultrasound
- Targeted laboratory tests based on suspicion (TSH, prolactin, androgens)
- Chlamydia swab for contact bleeding
What do the findings mean?
A broad, untargeted hormone panel rarely helps with irregular periods and often causes more uncertainty than clarity. A few targeted values, chosen based on symptoms and ultrasound findings, are more useful.
Contact bleeding is usually harmless
it is often due to cervical ectopy or ectropion – where the delicate, glandular tissue from the cervical canal extends somewhat onto the outer surface and is particularly well supplied with blood. Recurrent contact bleeding is still worth checking once, to rule out other causes (inflammation, polyp, rarely changes to the cervix) – especially if cervical cancer screening is not up to date.
Treatment
Possible approach.
Watchful waiting
For expected causes (life stage, harmless patterns), observation with a cycle app is often enough.
Whether to treat is an individual decision
some women simply want to understand their cycle, others prefer calmer, more predictable bleeding. What matters is what affects you – not a lab value.
Medication
If the cause is contraception-related and the bleeding is bothersome, we adjust the method. With thyroid dysfunction, the cycle often normalises once the thyroid is treated. With PMOS (formerly PCOS), therapy is guided by the goal (cycle, skin, desire to have children). If a calmer cycle is desired, hormonal methods – combined pill, progestogen preparations or hormonal IUD – can regulate or reduce bleeding. No one has to take hormones if they don't want to.
Surgery
For polyps or fibroids, a minor procedure may be appropriate depending on findings – for example a hysteroscopy.
Prevention
What you can do yourself.
- Track your cycle with an app or calendar – this makes assessment easier
- Take a pregnancy test first if the period is absent
- Always have bleeding after menopause assessed
- Have recurrent contact bleeding checked once
- Review your contraceptive method if the bleeding pattern is bothersome
- Keep cervical cancer screening up to date
The cycle – what is normal
28 days is an app setting, not a norm
The number 28 comes from a calculation model, not from biology. Cycle apps need a default value in order to display anything at all – they assume 28 days and ovulation on day 14 and calculate from there. If your body does not follow that, the app's prediction is wrong, not your cycle.
A cycle length between 24 and 38 days is considered normal. Bleeding arriving at exactly the same interval every time is the exception, not the rule. Variations of a few days from month to month are entirely ordinary, and longer intervals are not in themselves a disease. The body is indifferent to the calendar – it follows the interplay of hormones, sleep, stress, weight and life stage, not a number.
What a longer cycle means in practice
The real difference is not a medical one but a practical one
with long or fluctuating cycles, ovulation cannot be predicted. If you want to become pregnant, you cannot derive the fertile window from the calendar – it shifts along with the cycle, and an app showing «ovulation today» in a 45-day cycle is simply guessing.
That does not mean fertility itself is poorer. It means that sex «on schedule» according to a calendar does not work. Ovulation tests (LH in urine), observing cervical mucus or cycle monitoring with ultrasound in the practice are helpful – and otherwise regular intercourse spread across the cycle rather than on supposedly exact days.
The cycle as a health signal
The cycle responds sensitively to whatever else is happening in the body. A marked, newly appeared change is therefore a signal worth noting: significant weight change, pronounced stress, a lot of sport, thyroid function, PMOS (formerly PCOS), the start of perimenopause. A routinely ordered broad hormone panel adds nothing here – testing is targeted, based on suspicion.
You should seek assessment if
bleeding is absent for more than three months, a previously regular cycle suddenly changes, bleeding occurs after menopause, or pregnancy has not occurred for over a year.
One appointment. One main concern. So we can give you our full, unhurried attention, we address one main topic per appointment. We're happy to schedule additional or complex questions in a separate appointment. This is what allows consultations to run on time and without long waiting times – thank you for your understanding.
Frequently asked questions
FAQ.
Related topics
Keep reading.
- Annual check-up and Pap smear
Cycle work-up as part of the annual check-up in Basel.
- PMOS (formerly PCOS)
- Painful Periods
- Bioidentical Hormone Therapy
- Fertility
Cycle monitoring and work-up when pregnancy does not happen.
- IUD
Medically responsible.
Dr. med. Anna Margareta Wagner is a board-certified FMH specialist in gynecology and obstetrics with her own practice at Spalenvorstadt 3 in Basel. Special focus on surgical gynecology; further focus areas: gynecological check-ups, colposcopy and dysplasia consultations, intimate surgery, pregnancy care, and consultations for girls and adolescents.
- FMH specialist certification in gynecology and obstetrics
- Special focus: surgical gynecology
- SGGG member
- Certified colposcopy diploma
- Languages: German, English
- Service area: Basel-Stadt, Basel-Landschaft, northwestern Switzerland
The content on this page is reviewed regularly against current specialist medical recommendations.
Sources
Scientific references.
Your questions – discussed in a safe space.
Every situation is individual. During your consultation, we take the time to review your findings and find the right next step together.