Most women will experience missed periods or irregular periods in their lifetime.


Menstrual irregularities include changes in timing, frequency and volume of your period.

“So why are my periods abnormal?”

This article answers your questions about the causes of irregular periods.

7 Reasons for your menstrual irregularities

1. Menarche & Menopause

 There are specific times in a woman’s life when she is prone to irregular periods, namely at the start of menstruation (menarche) and at the end (menopause). Cycle length, duration of bleeding and amount of bleeding can all vary significantly during these 2 periods, and these irregularities can last for several months.

2. Pregnancy

Pregnancy is one of the commonest causes of a missed period. Unsure? Check by using a home kit, or getting a blood test. Pregnancy-related complications such as miscarriage and ectopic pregnancy can cause a late period, with abnormal bleeding. Breastfeeding after pregnancy also delays the return of your periods.

3. Weight

Fluctuations in body weight can interfere with your cycles. Irregular periods, or a missed period or two can occur if you’ve gained or lost a significant amount of body weight.

4. Exercise

For the ultra fit amongst us, participation in endurance sports or intensive exercise results in reduction in body fat, to levels which may not support regular hormonal function.
For the average female, the effects of exercise may be more evident in times when you have newly initiated exercise, or increased the intensity of your previous regimen. You may experience missed periods or abnormal periods for a few months, but this phenomenon is usually transient.
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5. Stress

Experiencing a tough time at work or at home? That might potentially be wrecking havoc on your hormones, causing your periods to be irregular, late, or lighter than usual.

 6. Birth control

The Pill, or other forms of birth control, usually have the advantageous effect of regulating or reducing periods. However, different types of birth control can influence your periods differently. Depending on the type of birth control you’re using, you may have missed periods, irregular periods, lighter periods, or no periods at all.
If this is interfering with your lifestyle, speak to your doctor about swapping to an alternative form of birth control.
Read more about contraception here.

7. Hormonal imbalance 

Period cycles are controlled by several hormones in the female body. Polycystic Ovarian Syndrome (PCOS) is a hormonal condition which results in irregular periods, lighter-than usual, or missed periods. Associated symptoms include male pattern balding, acne, weight gain, abnormal and excessive hair growth and infertility. This condition is common, affecting up to 15% of reproductive-age women.
Want to know more about period problems?
Click to read about heavy bleeding/heavy periods, and bleeding after sex.


Need a Female Doctor?

Having Women’s Health concerns? Please visit us or contact us at our GP Plus Clinics in Singapore. We are open on weekends too. For more information, please visit DTAP Clinic website, or email them at


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  1. elaine
    elaine says:

    What can i do this that about 2 months already i had an irregular menses almost every 4-5 days my menses came then gone after 2-3 days? Last march this year i had long term menses and heavy i went to the doctor then i had done my ultrasound but everything is normal.? What must i supposed to do? Thank u…

    • Dr Rachel Ng
      Dr Rachel Ng says:

      Hi Elaine, thanks for your enquiry. Your bleeding pattern does sound abnormal.
      May I suggest that you come into clinic to let me do a proper examination, and some investigations? I will be at our Bencoolen clinic most days, do call 68844119 to schedule a time.

  2. afrina
    afrina says:

    hi I’m kindda worried of my menstrual cycle like usually after my menses,for a short while I would have a brown stain and then my menses would end but this time it won’t stop like I would end my menses and it would usually have the brown stain like every time but then I am not sure what is happening like suddenly,a small amount of blood comes out and I’m worried till now it won’t stop…what should I do??

    • Dr Rachel Ng
      Dr Rachel Ng says:

      Hi Afrina,

      How many days have you had the bleeding/discharge now?
      Please come to clinic to let me check this out for you. You may require medications to stop the bleeding, and some further tests to investigate the cause of this abnormal bleeding.

  3. Jenny
    Jenny says:

    Hi, I’m currently a 16 year old student who enjoys exercising. Ever since I get really into running, (run 4 times a week, around 45-60 min each time), I started missing my periods. I have missed 2 already. I’m wondering if this is normal as I’m really worried.

    • Dr Rachel Ng
      Dr Rachel Ng says:

      Hi Jenny,
      Exercise and weight loss can sometimes interfere with the regularity if your periods. However, there are other important causes such as hormonal imbalances or pregnancy that can also result in missed periods.
      If possible, come into clinic to let me do a proper checkup for you? We can decide on how to further investigate this.
      I’m practicing at our Women’s Health branch at Bencoolen, please feel free to call or drop by.

      Dr Rachel Ng

  4. Joycelyn
    Joycelyn says:

    Hi Doctor! I’m 25 years old who just started working. I have irregular menses every since i started them when i was 11 years old. So i may missed my menses by one or two month at most. However my last menses was end of sept 2015. i thought the stress of finding a job and starting the job contributed to late menses, but i still do not have it. Should i come to the bencoolen clinic to do a check up? as well as a basic health screening? How much will it cost in total? Which sunday should i drop by? Thank you!

    • Dr Rachel Ng
      Dr Rachel Ng says:

      Thank for your your enquiry Joycelyn.

      It would be useful for you to come into clinic to have full assessment and investigations performed for your menstrual issue.
      May I suggest you call our Bencoolen clinic at 68844119, so we can set up an appointment for you?
      look forward to hearing from you!

      Dr Ng

  5. Jhez
    Jhez says:

    Hi, I’m currently 22 years old. I had my last period November so it means I’m already 3 months delayed menstruation. How can I cure or do you have any suggestion such as remedies to stop my irregularity on my monthly periods? Thank you in advance.

    • Dr Rachel Ng
      Dr Rachel Ng says:

      Hi Jhez,

      Missed periods maybe caused by many different factors, including lifestyle, stress, hormonal imbalances and pregnancy.
      It would be useful to do some tests to fully investigate your delayed periods.

      If you’d like to come by clinic, I would be happy to help you out with this. I can be reached at 68844119.

      Yours, Dr Rachel Ng

  6. Shermin
    Shermin says:


    I have been having irregular periods since i started my menses. It has always been quite irregular and recently it became regular for 3 months but then it stop coming. Now i have missed my period for 2 months. I did pregnancy testes and all are negative. Im quite worried. Am i sick or something? What can i do about this?

    • Anonymous
      Anonymous says:

      Hi Shermin,
      I suggest that you come into clinic – will need to speak to you about your menstrual and gynaecological history, and then proceed with some tests.

      Do pop into our women’s center at 180 bencoolen street, or ring us at 68844119.

      Dr Ng

  7. Gina
    Gina says:

    My menstruation stop last yr Oct. Thinking I am having menopause as I am now 54. Instead last 2 days I start having mensturation and the flow is quite heavy. Please advise

    • Anonymous
      Anonymous says:

      Hello Gina,

      Post menopausal bleeding is definitely abnormal. Please come in to let us do a proper pelvic examination for you.

      Dr Ng

  8. jay
    jay says:

    Hi, I’m 23 years old and March 12 – 15 was the date of my last period. This is a total of 76 days. I am a lesbian and haven’t had any sex with guys – although I’m still sexually active with my partner. Healthwise – I am a healthy weight and haven’t noticed much changes in my body.

    Should I be concerned? How long should I wait before i visit the doctor to have my body checked? Would a normal GP suffice or should I visit a gyne? What kind of tests would they run? Thanks!

    • Anonymous
      Anonymous says:

      Hi Jay,

      You’re welcome to come in to clinic, we can help to perform some basic blood and imaging tests for you first.

      Just drop in or give us a ring at 68844119.

      Dr Ng

  9. Anonymous
    Anonymous says:

    Hi im 31 years old.having A problem about my menstruation. I only have 1 time menstruation in A year… Pls let me know what should i do…
    Thank u

  10. Nura
    Nura says:

    Hi, i am 25 this year .. i am 6 days late period and i have nausea on/off and i have abdominal pain on the left side ..i have check pregnancy test came out negative ..
    Pls advise ..
    Thank you

  11. joann
    joann says:

    I didn’t have my period for 3-4 month already. And recentl my stool have blood. The bowl was red. I’m 23year old , having irregular menses but never missing my period before . Should I monitor a few more week ?