Generally, a period with dark and low volume of blood is normal and does not indicate any health problems, especially if it occurs at the beginning or end of menstruation. However, when this type of menstruation is recurring, it can be a sign of hormonal changes, uterine problems, stress or sexually transmitted diseases, for example.
This can also happen when women start taking the contraceptive pill for the first time, change the pill or use the morning-after pill. In these cases, menstruation can also become darker or have the color of coffee grounds, returning to normal in the next cycle.
Main causes of dark period blood
Menstruation blood, which is black, brown, or similar to coffee grounds may be caused by:
A small amount of pinkish, brownish or dark reddish bleeding is common in the first weeks of pregnancy because the embryo is attaching itself to the walls of the uterus.
However, when this bleeding occurs at a later stage of pregnancy or is accompanied by other symptoms such as abdominal pain, shoulder pain, dizziness or excessive fatigue, it may indicate the development of ectopic pregnancy or miscarriage, so it is recommended you go to the obstetrician to verify if there’s any problem.
2. Emotional changes
Some changes in a woman's emotional state, such as excessive stress or depression, can affect the structure of the uterus by reducing the thickness of its walls. This change delays the peeling of the cells and, therefore, facilitates blood oxidation, making the period darker.
3. Hormonal changes and menopause
Hormonal changes because of thyroid problems, or even menopause, commonly cause the period to darken and come in small amounts. This change is also very common when switching contraceptive pills or when the woman is not breastfeeding very often, and the breastfeeding pill is not enough to avoid bleeding.
4. Sexually transmitted diseases
Sexually transmitted diseases caused by bacteria, such as gonorrhea or chlamydia, for example, cause a more rapid degradation of menstrual blood, turning it darker. In addition, this type of period is usually accompanied by a foul smell, brown discharge before or after menstruation, pelvic pain and a fever above 38º C.
5. Endometriosis and other conditions
Endometriosis is the growth of endometrial tissue outside the uterus. This type of problem and other conditions such as adenomyosis can cause severe pain in the pelvic region and dark blemishes, similar to the color of coffee grounds, that can occur both during and between menstruation.
In these cases, the period, besides being dark, can also last up to 7 days. In case of suspicion, you should go to the gynecologist for an examination, analyses and recommendations for antibiotics, or another form of treatment, such as surgery.
Another situation in which dark period blood is normal is in the postpartum stage, because the uterus takes about 45 days to return to its normal size and there’s bleeding during this period. At this stage, this bleeding isn’t exactly menstruation, but the coloration is dark and may confuse many women. However, this is normal and expected.
If your period comes with clots, read 7 reasons for menstrual blood clots.
When should you go to the doctor?
Changes in menstrual bleeding are usually normal and do not indicate problems, but you should go to the gynecologist if other symptoms or signs also appear, such as:
- Period lasting more than 7 days
- No period for more than 3 months;
- Vaginal bleeding between periods;
- Pain in the intimate area;
- Fever above 38º C;
- Pale skin in general or below the nails.
It is also important to remember that in cases of suspected pregnancy, the appearance of dark bleeding, with clots or in large quantities, is also a reason to see the doctor, because it may be a miscarriage, and a curettage may be necessary to clean the uterus.