Why Is My Period Late (Again)?” Here are 3 Causes of Irregular Periods and How You Can Manage It


A woman’s first instinct is to suspect that she is pregnant when her period is late, especially if she is of the reproductive age group and she is sexually active. But late periods are not always a sign of pregnancy. They could signal other emotional or health complications as well.

The Menstrual Cycle in a Nutshell 

Defined by the time frame between the first day of menstrual bleeding to the next time the bleeding begins again, a woman’s menstrual cycle could last on average from 21-35 days. 

For a woman to conceive, she must have unprotected sexual intercourse when she is ovulating – this is the time during the menstrual cycle when the egg is released from the ovary and travels to the fallopian tube where it can be fertilized by the sperm. Otherwise known as the “fertile window”, ovulation usually takes place between day 8-19, depending on the length of the menstrual cycle. 

While a delayed menstrual cycle can be possible due to pregnancy, it could also be influenced by other external factors as well. 

The menstrual cycle differs from individual to individual and could be influenced by genetics, lifestyle, diet and health. Some people get their periods every 30 days while others have cycles where their periods come between 21-35 days. Some might even have a natural cycle of up to 45 days!

If you notice that your menstrual cycle is longer than usual or the bleeding is heavier than usual, it might be a cause for concern. 

Top 3 Causes of Irregular Periods & What to do About Them

Pregnancy is impossible if you have not had sexual intercourse, so what explains your late period?

Here are 3 possible reasons other than pregnancy that explain why your period might be late. 

1. New Extreme Diets or Workout Regime

If you have ramped up your workout intensity and reduced your food intake drastically to cut a few kilos, you could be disrupting your menstrual cycle unknowingly. 

The combination of intense workouts and low-calorie diets could put unnecessary stress on the body. This stress affects the hypothalamus (a part in the brain that is responsible for releasing hormones) which affects the production of hormones that are meant to regulate your monthly periods. This in turn leads to no periods or very irregular cycles. 

Extreme changes to your workout and diet could hence cause a significant change in your menstrual flow. 

How to Manage

Instead of a sudden change, adjust your diet and workout gradually. It is important to do things in moderation and not go on extreme diets or exercise excessively. Drastic changes could put unnecessary stress on the body, which could lead to unwanted consequences on your health.

You should also abstain from extreme and excessive exercise but stick to a regular routine that you enjoy. 

On the contrary, obesity and being overweight can also lead to abnormal hormonal problems which can lead to irregular periods.

Hence, the key is moderation and to maintain a healthy weight and lifestyle.

2. Sudden Stress

Like physical stress, emotional stress could interfere with hormonal regulation in your body and disrupt your monthly periods. 

Not only can stress disrupt your menstrual cycle, but the hormonal imbalance could also cause breakouts and mood swings. This may also lead to unhealthy habits such as stress eating junk food. 

Managing Stress Healthily

Stress is inevitable, especially for the modern busy working woman. But it is important to manage stress healthily to improve your health and overall well-being. 

Relieve stress with healthy and regular exercise or self-care. Make time for rest and give yourself some breathing space when you feel overwhelmed. It is important to ensure you get adequate rest at night as well.

3. Hormonal Problems 

There are various hormonal issues associated with irregular periods. These include:

1. Abnormal thyroid hormone function: over or under-function of the thyroid gland can lead to irregular periods or heavy bleeding 

2. Polycystic Ovarian Syndrome (PCOS): a condition caused by “hormonal imbalances”, PCOS is a well-known cause of irregular periods. This condition is characterized by polycystic ovaries that have multiple follicles which might cause irregular menstruation. PCOS is also associated with excessive production of male hormones which can lead to symptoms such as hirsutism (excessive hair growth) or acne. PCOS is a common cause of irregular periods, especially in younger women 

What To Do About It

If you suspect you have any of the aforementioned hormonal issues, consult a female doctor early for further checks to get to the root of the issue. You may be asked to do blood tests, get a pelvic examination, a pelvis ultrasound and a PAP smear

Your doctor might also recommend hormonal medications or other treatment methods to resolve the issue. 

When You Should Be Concerned

While not everyone’s menstrual cycle functions like clockwork, consistent irregularity might signal underlying health conditions. Tracking your periods regularly and seeking help early would be useful in helping your doctor determine the cause of your irregular menstrual flow. 

If you have not had your period for a while or you find that the bleeding has been abnormally heavy, seek advice from a female doctor as soon as possible! 



Dr Michelle Chia

Medical Director

After graduating from the National University of Singapore, Dr Michelle's journey allowed her to train in Women's Health and Aesthetic Medicine. Her experience has led her to be featured on multiple media platforms including Radio Stations and prominent Magazines like Her World, Women's Weekly and CLEO. Her work has also received recognition both locally and internationally in several Medical Conferences.

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Ezra Clinic is a Women’s Health, Wellness and Aesthetic Clinic that is conveniently located at the top floor of Royal Square Medical Suites in Novena, Singapore’s Medical Health Hub.

Helmed by Dr Michelle Chia, Ezra Clinic is your chosen one stop clinic for all your Women’s Health and Wellness needs.


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