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Is heavy menstrual bleeding normal? And what does eating pineapple have to do with it?

An expert tells CNA Lifestyle why you might want to have a doctor check it out – and why your mother was right about a certain fruit.

Like many women, Amanda (not her real name) dreads that time of the month. But not so much for the bloating, breast tenderness, mood swings, or even painful cramps. The 32-year-old has to prep for each month’s menstruation as if she were almost going on a day trip.

“I have a drawstring bag stocked with a full pack of sanitary napkins for heavy flow, heavy-duty tampons and at least one change of panties and clothes,” said Amanda, who works in marketing and often trudges from meeting to meeting with a gym bag even though she doesn’t work out.

That’s because her menstrual flow is so heavy, she needs to change her double sanitary protection every hour. And even so, that may not guarantee she doesn’t stain her clothes. To get around it at work, she sits on a folded, dark-coloured towel to avoid staining the office chair.

Generally, heavy menstrual bleeding occurs most frequently among women aged between 25 and 49.

Bedtime is just as inconvenient for Amanda. She often has to get up to change her pad and tampon during the night or her bed would look like “a murder scene the next morning,” she said. Yet, Amanda has never considered seeing a gynaecologist for her excessive bleeding. “I just thought it is the normal amount women lose,” she said.


What Amanda experiences every month are classic symptoms of what is medically known as menorrhagia, which can also include large blood clots, and periods that last longer than a week. She isn’t alone in thinking that her heavy bleeding is normal. The menstrual flow experienced by different women of different ages varies vastly, said Dr Jason Lim from Singapore General Hospital’s Department of Obstetrics and Gynaecology. And because every woman’s flow is different, women end up with a subjective picture of what “normal” is when they compare notes with each other.


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Furthermore, there isn’t significant data on the incidence of menorrhagia among Singaporean women, said Dr Lim, who is currently leading a study on its prevalence in Singapore. “Generally, heavy menstrual bleeding occurs most frequently among women aged between 25 and 49,” he said.



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For the record, women lose about 30ml to 40ml (two to three tablespoons) of blood every month on average, according to HealthHub, a website by the Ministry of Health and Health Promotion Board. “Most women do not necessarily have to change their sanitary pads every two hours,” said Dr Lim. But in menorrhagia, the amount of blood lost can be greater than 80ml every month – enough to soak through a pad every hour for a few consecutive hours, according to the Mayo Clinic website.


Other than the inconvenience, a more worrying effect of menorrhagia is anaemia. “It is a condition where one lacks sufficient red blood cells to carry adequate oxygen to the body’s tissues. Symptoms of anaemia include pallor, breathlessness on exertion, lethargy, giddiness, chest discomfort and/or poor concentration, which may occur during or after a period,” said Dr Lim.

Signs of anaemia caused by heavy menstruation can include giddiness. (Photo: Pexels/Renzy Atibagos)

Having said that, not every woman who experiences heavy periods is prone to giddiness and fainting spells. “Blood loss results in anaemia of varying degrees and this has a multitude of consequences to the general health of an individual,” said Dr Lim. “Moreover, the same volume of blood loss may be well-tolerated by one but may be medically dangerous for another.”


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To determine the severity of anaemia, the haemoglobin (a red protein that carries oxygen from the lungs to the body’s tissues) level is assessed. “In my practice, I have come across women with very severe anaemia due to heavy menstrual bleeding. The normal level of haemoglobin is approximately between 11.5g/dL and 14.0g/dL but theirs was lower than 5.0g/dL. This group of women would require a blood transfusion to replace their blood loss,” said Dr Lim.


Remember your mum’s nagging to avoid eating pineapple when you’re on your menses as it will induce a heavier flow? There might be some truth to that. “Certain foods may contain specific chemicals which may interfere with our body’s blood clotting system, thereby resulting in an increased propensity to bleeding,” said Dr Lim. “An example is the bromelain found in pineapples which has anti-inflammatory properties.”

Certain foods may contain specific chemicals which may interfere with our body’s blood clotting system, leading to a heavier flow. (Photo: Pexels/Miguel A)

However, Dr Lim stressed that there is no robust scientific evidence on the “cause-effect relationship of foods and such chemical interactions in our bodies”. “Nonetheless, if you notice a certain relationship between specific food intake and increased menstrual bleeding, it may be wise to avoid these foods,” he added. 

Meanwhile, hormones certainly play a definite role. Oestrogen and progesterone levels affect the endometrium that lines the uterus wall; this lining grows and gets shed each month to become menstrual flow. In menorrhagia, a hormonal imbalance may cause the endometrium to develop excessively, leading to a heavy flow when it is shed, according to HealthHub.

Certain foods may contain specific chemicals which may interfere with our body’s blood clotting system, thereby resulting in an increased propensity to bleeding.

There are also gynaecological factors that range from endometrial cancer to fibroids (thickened muscle tissues), polyps (small growths on the cervical or uterine wall) and the inflammation or infection of the vagina, cervix, or pelvic organs, according to HealthHub. Another condition that can cause heavy flow is adenomyosis, in which the endometrium grows into the muscle wall of the uterus. 

Thyroid disorders and kidney disease can create menorrhagia. (Photo: Pexels/Kat Jayne)

“There are also some medical conditions which may be related to heavy menstrual bleeding in women,” said Dr Lim, citing thyroid disorders as some of them. “A dysfunction of the thyroid gland may result in changes in the menstrual flow and cycles as the thyroid hormone has an indirect effect on the hormonal balance in women.” Such disorders may be characterised by tremors of the hands, a change in bowel habits, or intolerance to heat or cold temperatures, he said.

“Another medical condition is kidney disease. The dysfunction of the kidneys may have an adverse impact on the metabolism of the female hormones,” said Dr Lim. “Kidney disease may bring about changes in the urine output and affects the skin complexion.”


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Treatment is determined after confirming the cause of the heavy menstrual bleeding. “This would require investigative tests such as an ultrasonography of the female pelvic organs, a physical examination, cervical smears, and even using detailed radiological imaging tools such as computed tomography scans,” said Dr Lim, who added that oral hormonal tablets, injections, intrauterine devices and surgery may be used to treat the issue.

Find out more about heavy menstruation and abnormal bleeding on Nov 9, 12.30pm to 3.30pm at the National Heart Centre Singapore, level 7, auditorium. Free admission. Limited seats. 

Source: CNA/bk