Brief Answer:
hypomenorrhoea

Detailed Answer:
Hello,
Thanks for the query to hcm,
Scanty menstrual periods are periods in which the duration of blood flow is less than two days or the amount of blood flow is less than 80ml. This is known as hypomenorrhoea. Causes of Scanty Blood Flow During the Period
1. Constitutional Causes
In some women it may be found that the woman's mother and/or sisters also have decreased blood flow during their periods. Pregnancy can normally occur with with this type of decreased flow during the periods.
2. Hormonal Causes
a. Extremes of Reproductive Lives
Scanty menses or periods can occur normally at the extremes of reproductive life - that is, just after puberty and just before menopause. This is because ovulation is irregular at this time, and the endometrial lining fails to develop normally.
b. Anovulation
Hormonal problems at other times can also cause scanty blood flow. Anovulation due to a low thyroid hormone level, high prolactin level, high insulin level, high androgen level and problems with other hormones can also cause scanty periods.
c. Oral Contraceptive Pills (OCP)
Scanty menses can also occur after long term use of oral contraceptives as a result of progressive endometrial atrophy. Complete loss of periods after oral birth control pills is known as postpill amenorrhea.

3. Uterine Cause
Blood flow during a period depends on the normal growth of the endometrium (internal uterine lining). If there is a scar inside the uterus, the surface area of the endometrium may be smaller than normal. Scarring can occur after operations on the uterus like a myomectomy (removal of fibroids), after radiation treatment or in conditions like Asherman's syndrome. This may cause less blood flow during the periods.
4. Emotional/Stress Causes
Sometimes psychological factors can come into play. Emotions and stress can act on the centers in the brain that stimulate the ovaries during the ovarian cycle. If these centers in the brain are suppressed due to stress, they fail to stimulate the ovaries leading to less or no production of estrogens and hence scanty menses or periods.
5. Other Causes
Other causes that can cause scanty or decreased blood flow during the periods are excessive exercise, crash dieting, change in the environment (such as by changing a job), stress due to exams, excessive excitement due to an upcoming event can all cause scanty or less blood flow duering the periods.
So in your case the most likely cause is stress induced here and it should normalise in next few cycles. You need to maintain a menstrual calendar for next 2 more months to understand the pattern of bleeding completely , which if continues then a hormonal profile and an ultrasound pelvis shall be required.
Regards

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