Menstruation and Irregular Periods Singapore – Here’s What You Need to Know
Home » Menstruation and Irregular Periods Singapore – Here’s What You Need to Know
What is the menstrual cycle?
The menstrual cycle, also known as menstruation or periods in Singapore, occurs when there is shedding of the uterus lining (otherwise known as the endometrial lining) – which comprises blood and tissue. It helps the body prepare for pregnancy and typically starts at puberty and ends in menopause; this is when menstruation stops for an entire year [1].
Menstrual cycles begin at puberty and end at menopause.
The menstrual cycle takes place as a result of hormones and has three phases:
Follicular phase: this refers to the first half of the menstrual cycle and starts from Day 1 of your period, lasting until ovulation. The first few days (lasting up to a week) are characterised by the shedding of the uterine lining, which women recognise as their period blood. The ovaries then start developing a few follicles (each containing an immature egg), with one becoming the dominant one, which continues to mature. This phase is also characterised by endometrial proliferation [2], whereby oestrogen stimulates the thickening of the uterine lining in preparation for potential embryo implantation should the woman fall pregnant.
Ovulation phase: ovulation typically occurs mid-cycle, e.g. in a 28-day cycle. It usually occurs around day 14 but varies depending on the cycle. During ovulation, the mature egg is released from the dominant follicle, and this egg is picked up by the fimbrial end of the fallopian tube, where it waits to meet a sperm.
Luteal phase: following ovulation, the luteal phase starts – marking the second half of the menstrual cycle. The follicle that releases the egg forms a corpus luteum, which begins secreting progesterone to stabilise the uterine lining to prepare for a potential pregnancy. If there is no pregnancy, the uterine lining sheds, and the next period occurs.
How long is a normal menstrual cycle?
A normal menstrual cycle varies between individuals in Singapore, but the average length is usually 28 days. However, a normal interval between periods (from Day 1 of one period to Day 1 of the next period) is defined as anywhere between 21 to 35 days [3]. It is also important to remember that the number of days between each period will vary between women, even within the same individual. Various things can cause the length of your menstrual cycle to change; these include:
Stress: high stress levels can result in hormonal disruption, resulting in disturbances in ovulation [4]. Anovulation is when the ovaries do not release an egg during the menstrual cycle, resulting in shorter/longer cycles or irregular periods. In extreme circumstances, this can even lead to secondary amenorrhoea, defined as the absence of menstruation in a person who previously had periods [5]. Other ways that stress can impact menstruation include increased cramps, bloatedness, and mood swings related to periods.
Sickness: sickness or illness can affect one’s menstrual cycle, although the extent and impact depends on the specific illness, its severity and the individual’s overall health [6]. Certain conditions can result in hormonal disruptions and affect the regularity of ovulation, resulting in menstrual disturbances.
Hormones: hormones outside the reproductive sphere can also cause disruptions in one’s menstrual cycle [7]. Most commonly, thyroid disorders such as hypothyroidism or hyperthyroidism can manifest in irregular periods or erratic menstrual bleeding. Hormonal imbalances within the reproductive sphere can also result in menstrual disturbances, commonly PCOS (polycystic ovary syndrome), where there is hyperandrogenism (increased levels of testosterone) that typically presents with abnormal menstrual patterns. Natural hormonal fluctuations can also occur in the pubertal and peri-menopausal transition phases.
Lifestyle: significant weight changes, particularly within a relatively short period of time (both involving weight loss or weight gain), can affect hormonal balances and, hence, menstrual irregularity [8]. Women with eating disorders, obesity or exercising excessively are all susceptible to menstrual disturbances.
Medications: some medications, including hormonal contraception (oral/implants), psychotropic medications, etc, can influence one’s menstrual patterns, and it is important to discuss with your gynaecologist before starting on these.
Structural issues: things that affect the structural integrity of the female reproductive organs, namely endometrial polyps, uterine fibroids, ovarian cysts, etc, can impact one’s menstrual cycles.
Pregnancy and breastfeeding: pregnancy results in a temporary cessation of menstruation, and breastfeeding following childbirth typically results in a delay in the resumption of normal periods.
For most women, a typical period/menstruation usually lasts no more than seven days.
Breastfeeding following childbirth usually results in a delay in the resumption of normal periods.
What are the common symptoms of menstruation in Singapore?
In addition to bleeding, the other symptoms associated with menstruation include:
Cramping: menstrual cramps, otherwise known as dysmenorrhoea, are commonly experienced amongst women and result from the uterus contracting to expel its lining. Some women perceive more menstrual cramps than others and are usually able to manage them with conservative measures such as heat packs, simple analgesia, etc.
Mood swings: some women may experience irritability, mood swings or changes in their emotional state, more commonly in the lead-up to their menstruation due to hormonal fluctuations. If it is cyclical and affects your ability to function, it may be part of PMS (pre-menstrual syndrome).
Bodily symptoms such as breast tenderness/abdominal bloatedness: hormonal fluctuations can also lead to breast tenderness/sensitivity in the lead-up to menstruation, with a sensation of abdominal bloatedness/water retention. Some women may also experience fatigue, headaches, or appetite changes.
Changes in vaginal discharge: some women may notice changes in colour and consistency of their vaginal discharge depending on the phase of their menstrual cycles; immediately before and after ovulation, the cervical mucus/vaginal discharge may appear more clear and slippery, whilst, after ovulation, it typically changes to a more sticky texture.
Mild cramping during menstruation is normal as the uterus sheds its lining.
What is an irregular period?
An irregular period is when the gap between each menstrual cycle is less than 21 days or more than 35 days. There are also other characteristics of abnormal periods; these are:
Menstrual flow: periods that are lighter or heavier (requiring frequent pad changes) than normal are signs of an abnormal period. If you find yourself changing your pad on an hourly basis, passing a fair number of sizable clots, flooding your pad in a relatively short time, or having frequent “accidents” of staining your underwear/pants/chairs, then you should seek a gynaecologist’s opinion.
Length of menstrual cycle: for intervals longer than the typical 21-35 days, it is referred to as oligomenorrhoea. Women with this usually experience irregular periods that occur less frequently than normal. The most common cause of this is PCOS (polycystic ovary syndrome), where there is an issue with hormonal imbalances and hence ovulation [9]. On the other end of the spectrum, polymenorrhoea is a menstrual cycle characterised by abnormally short intervals between periods, i.e. shorter than 21 days. This typically results in a woman experiencing periods that occur more frequently than normal.
Missing periods: missing periods, also known as amenorrhoea, can be subdivided into primary and secondary amenorrhoea. Primary amenorrhoea refers to the absence of menstrual periods in a young adolescent who has yet to experience her first menstruation, usually by the age of 16 [10]. Secondary amenorrhoea refers to the absence of menstrual periods in a woman who previously experienced periods – the most common reason being pregnancy, but also hormonal disorders like PCOS [5].
Prolonged periods: periods lasting beyond seven days are defined as prolonged and usually result from hormonal imbalances, structural issues such as uterine fibroids, endometrial polyps, ovarian cysts, blood clotting disorders, use of medications (such as anticoagulants or hormonal medications) or contraceptive implants, or underlying medical conditions.
Unscheduled vaginal bleeding: this is either known as intermenstrual bleeding (IMB), which refers to unscheduled bleeding that occurs in between menstrual cycles, or post-coital bleeding (PCB), which refers to unexpected bleeding following sexual intercourse.
Severe pain or nausea: if you experience bad menstrual cramps, i.e. dysmenorrhoea (this may occur in your lower abdomen/pelvis or radiate to the lower back/thighs) that affects your ability to function and quality of life, it is advisable to see a gynaecologist for further evaluation as you may have gynaecological conditions such as endometriosis, adenomyosis, uterine fibroids, endometrial polyps, pelvic inflammatory disease (PID), etc.
Ascending infection from the vagina upwards towards the uterus, fallopian tubes, and ovaries
Primary ovarian insufficiency
Irregular periods, oligomenorrhoea, period flow getting lighter and lasting for a shorter duration. May also be accompanied by vasomotor symptoms such as hot flushes, mood swings, insomnia, body aches, etc.
Loss of ovarian function before the age of 40, previously known as premature ovarian failure or early menopause
Uterine or cervical cancer
Unscheduled bleeding, heavy menstrual flow, abnormal vaginal discharge
Certain conditions may increase the risk of uterine/cervical cancer, including PCOS, obesity, HPV infection, etc.
Polycystic Ovary Syndrome (PCOS) is characterised by irregular periods, weight gain, acne, and hair loss.
Can you get pregnant with irregular periods?
While it may be challenging to get pregnant if you have irregular periods, it is not impossible. Here are some ways to increase your chances of conceiving:
Have regular sex: having higher sex frequency (every 2-3 days throughout the month) will increase your chances of conceiving naturally since you may be having irregular periods due to erratic ovulation.
Tracking your ovulation: this can be done in various ways, including ovulation tracking apps, urine ovulation test kits, blood tests, or even ultrasound scans. Tracking your ovulation and timing your sexual intercourse in accordance with that will increase your chances of getting pregnant.
Having a healthy lifestyle: this includes adopting a healthy diet, exercising regularly, reducing stress, getting adequate rest, and avoiding smoking/drugs/excessive alcoholic or caffeinated beverages.
Getting a fertility screen: your gynaecologist will be able to go through the various tests/investigations required for you and your partner to understand your fertility health and suggest potential solutions depending on the uncovered issues. If you are over 35, doing this sooner rather than later is advisable.
Is there a way to make an irregular period regular?
This depends on what is causing your irregular periods. If it is caused by certain lifestyle factors such as stress, unhealthy diet, or temporary medications/sickness, your periods can become regular again once these lifestyle factors are back to the status quo.
However, if your irregular periods are caused by medical conditions such as PCOS, you will need to discuss with your gynaecologist the appropriate management options, which should be tailored to your specific circumstances, e.g. fertility desires, timeline, etc and individualised accordingly.
With the help of your gynaecologist, you, too, can live a fulfilled life with irregular periods.
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Carr, B. G. (2018). The Normal Menstrual Cycle and the Control of Ovulation. South Dartmouth: Endotext.
Pilar Vigil, c. a. (2022). Chronic Stress and Ovulatory Dysfunction: Implications in Times of COVID-19. Frontiers in Global Women's Health, doi: 10.3389/fgwh.2022.866104.
Lord, M., & Sahni, M. (2022). Secondary Amenorrhea. Florida: Stat Pearls.
Thiyagarajan, D. K., Basit, H., & Jeanmonod, R. (2022). Physiology, Menstrual Cycle. Florida: Stat Pearls.
Shrinjana Dhar, K. K. (2023). Influence of lifestyle factors with the outcome of menstrual disorders among adolescents and young women in West Bengal, India. Scientific Reports.
Riaz, Y., & Parekh, U. (2023). Oligomenorrhea. Florida: Stat Pearls.
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