Women's Health

Irregular Menstrual Cycle

For most women, the ‘time of the month’ is somewhat dreaded, but for some, irregularity is a greater cause for concern. Obstetrician & Gynaecologist Dr Poon King Fu sheds light on the medical conditions that result in irregular periods.

Some women have 28-day menstrual cycles; others only get their period once every two months. Cycle length and duration vary widely among women. Generally, a normal regular cycle interval should be between 21 and 35 days. It is usually slightly heavier on the first two days, then lighter over the next four to five days.

For women who are still in the reproductive phase, a missed period may mean pregnancy while those above 45 may be experiencing the onset of peri-menopause (also known as ”˜menopausal transition’).

Heavy Bleeding vs Light Spotting

If you experience heavy bleeding that lasts over a week, it could be due to a gynaecological condition like an incomplete abortion, excessively thickened womb lining, infection, polyps, fibroids, intrauterine contraceptive device or cancer. It could also be due to a bleeding disorder, thyroid disease or the effect of drugs.

Light spotting or a missed period could be due to stress, rapid change of body weight, thyroid disease, threatened abortion, ectopic pregnancy or polycystic ovarian disease.

Polycystic ovary syndrome (PCOS) is a disorder with multiple possible symptoms. Infrequent or prolonged menstrual periods, excess hair growth, acne and obesity are all possible symptoms of PCOS.

In the case of some women, enlargement of a small but vital gland in the brain called the pituitary leads to elevated levels of a hormone that interferes with menstrual flow.

Higher frequency

If the interval is less than 21 days, go for a proper medical assessment. If your period is irregular, depending on the extent, it may mean something serious or totally benign. Hence, it is important to consult a medical practitioner for a proper assessment.

Main concerns

Women with irregular cycles generally have reduced fertility as they usually suffer from anovulation and hormonal imbalance. Irregular menses is usually associated with underlying hormonal imbalance. This can result in unpredictable sudden outflow with fainting episodes and anaemia. There is also an associated risk of cancer arising from prolonged stimulation of the lining.

On the other hand, irregular menses may also arise from underlying disease of the genital tract including infection, tumour or some bleeding disorder.


As irregular periods are often due to hormonal imbalance, hormonal medications constitute the main method for regulation. Other potentially useful ways to treat or improve the condition include reduction of stress and body weight.

Women with two episodes of bleeding within a month especially for two or more months should seek proper medical assessment soon to exclude the serious underlying conditions mentioned above. It is always better to be safe than sorry.

Article contributed by Dr Poon King Fu, an accredited doctor of Mount Alvernia Hospital.

Poon’s Clinic for Women Pte Ltd
Blk 108 Hougang Ave 1 #01-1259, Singapore 530108.
Tel: 6858 1233

Note : Please note that health information is provided to supplement the care provided by your doctor. It is not intended nor implied to be a substitute for professional medical advice.   Always seek the advice of your physician if you have any questions regarding a medical condition.