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Is it Normal for Teenagers to Have Irregular Periods?

M brought her 13-year-old daughter to see me theother day.

“Doc, my daughter started her periods about 2 years ago. Initially, her period was not regular every month. It may be delayed for two to three weeks. Her periods also vary in amount and duration in different months. She will bleed for 3-7 days and may need to change pads 3-4 times a day. But for this month, she has been bleeding for more than two weeks. The flow for the first week was so heavy that she stained her bed sheets twice at night. The bleeding is less now. She uses only one or two pads a day. My mother-in-law wants to give her some Chinese herbs but I prefer to seek your advice,” she said.

M's daughter looked pale and worried. She did not have other medical issues. Her BMI was normal. An abdominal ultrasound examination with a full bladder revealed that her reproductive organs were normal. Blood hormone tests of thyroid gland, pituitary gland and ovary were normal. Full blood count revealed that she was slightly anemic.

Irregular Periods in Adolescents

Most girls will get their first period between the ages of 10 and 15. Some girls will get their period earlier whilst some will get theirs later. The menses can be irregular in frequency, duration and the amount of flow. It usually takes about 2 years before they become regular.

Having an irregular period during puberty is normal. Parents need not be too anxious unless their daughters have other signs of health problems.

What Causes Irregular Periods in Teenagers?

A girl’s menstrual cycle is the number of days from the beginning of her period to the start of the next period.

During a menstrual cycle, one of the ovaries releases an egg in a process called ovulation. At the same time, hormone changes prepare the lining of the uterus to become thick in preparation for pregnancy. When the egg is not fertilized, the lining of the uterus sheds through the vagina resulting in a menstrual period.

Irregular menses in teenagers is due to anovulatory cycles in which the body does not ovulate monthly. This is because the brain centers that regulate menstrual periods have not yet attained maturity. Illness, rapid weight change and stress can aggravate the situation and make the cycles more unpredictable.

When should irregular periods be a concern?

Teenagers should seek medical advice if her:

• Regular menses becomes irregular

• Menses suddenly stops for more than 3 months

• Menstrual cycle is longer than 35 days

• Menstrual cycle is shorter than 21 days

• Menses lasts more than seven days

• Bleeding between periods

• Excess hair growth on the abdomen, face, or chin

• Severe menstrual cramps, pain, or clots

M thought the cause of her daughter’s problem was due to a recent bout of viral fever coupled with the stress from her studies. I treated her daughter with hormone and iron tablets. The bleeding stopped after 2 days. The menstrual cycle was regulated with medications for another 3 months. Her periods had returned to normal since then.

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