Blood clots during period may be normal, more often than not, blood clots may signal serious underlying medical conditions affecting the female reproductive system. Blood clots in period form when the body expel blood and the released anticoagulants during menses did not have enough time to clot the blood. If the blood clots in period blood persists or becomes excessive even after your period has elapsed, it may be a sign of serious medical conditions such as internal bleeding, membrane rupture, etc. So also your menstrual blood may become thinker and darker in color as it approaches the end of the period, this is normal.
Menstrual blood clots may be caused by any of the following:
This is primarily caused by genetic factors, ovarian cyst (minority of all causative factors), and cancers. It causes dips in progesterone which leads to shedding of the endometrium and other uterine tissues and dead blood cells. This may be seen as blood clots and other endometrial debris.
2. Polycystic ovarian syndrome (PCOS)
PCOS this characterized by irregular hormonal profile and irregular menstrual cycles which may give rise to heavy bleeding and passage of blood clots in period.
3. Blood clots during period may also be caused by uterine fibroid
Fibroids are fibrous tissues (mostly with unknown causes) which grows within the uterine wall, thus squeezing other organs. When it grows alongside with fetus, it may result in heavy vaginal bleeding and passage of blood clots occasionally, as well cause still birth due to fetal compression.
Early menopause or pre-menopausal stages causes dwindling levels of progesterone and estrogen. This causes abnormal shedding of the endometrial tissues which may result in bleeding.
5. Obstruction of menstrual blood
Blockages in the cervical orifice during menstruation may lead to agglutination of blood droplets into clots. This may be seen as a passage of period blood clots.
Certain drugs may produce physiological interactions which may lead to menstrual blood clots.
Premature abortion and miscarriages may cause intra-uterine manipulations which may result in period blood clots.
8. Deficiencies in iron supplement
There are several reports indicating iron deficiency and anemia as one of the risk factors for blood clots during period.
This is a hormone-dependent tumor which may cause intra-uterine manipulations. The resultant effect is oftentimes period blood clots. It may also be accompanied by abdominal pain and profuse periods.
10. Hormonal changes
Changes in hormonal profile such as progesterone, estrogen, thyroxine hormones causes changes in the uterine structures and menstrual periods. Low progesterone levels may cause vaginal spotting while on occasional basis, heavy bleeding may accompany low progesterone levels if the estrogen level keeps increasing.
Period blood clots is also common in women who just reached the menopause stage. This is due to the fact reproductive hormone levels fluctuates repeatedly before it finally wanes, this may cause structural adjustments to the endometrium and uterine blood vessels. With time, it will resolve.