During menstruation, the thick lining of your uterus breaks away. As you menstruate, natural anticoagulants (chemicals that help thin blood) are released in order to break down the thick blood before it leaves your body. During a heavy flow, these chemicals may not have time to break down the blood as it is expelled from your body faster. This is when the clots form.
Clots look like jelly-type blobs which can vary in size and colour. This means they can be quite worrying, especially if you hardly ever get them/if they are of quite a large size. The most important thing to know is that they are completely normal. Most people are heavy in the first few days of their period, as the lining of the uterus breaks away quite fast. Due to this, clots are most common at the beginning section of your period, however, if your periods are heavy throughout you may also experience clots during the whole duration. It is normal for the consistency of your period blood to change from month to month, which can depend on your diet and lifestyle however it is mainly just how your body works naturally.
You can do a range of different things to decrease the formation of blood clots, such as lay off foods high in Vitamin K, instead, it is recommended you eat fruits high in Vitamin C to help the release of anticoagulants. Exercising regularly and making sure you are a healthy BMI can also help to reduce the heaviness of your period. There are also suggestions that going vegan can help your flow as it messes with your bodies hormones less than consuming animal products does.
Although clots are normally nothing to worry about if your period is regularly heavy and you are passing many large, thick blood clots it is best to go to see a doctor. Visiting your doctor will help eliminate any other problems, such as a possible miscarriage, menopause or most commonly endometriosis. You may also be suffering from anaemia, an iron deficiency which will increase the flow of your period. If the test comes back positive you will be given iron supplements which may help the clots. Or, the doctor may recommend prescribed tranexamic acid which helps reduce your blood flow by adding more anticoagulants into your body which will, therefore, decrease the clotting. Oral contraceptives are also an option, as heavy bleeding is sometimes caused by hormonal imbalances and contraceptives work to balance these out.
It is important to track your period, including the flow and the length in order to notice any changes which may be indicators of some health issues. Menstrual cups are the best form of period product to use as they collect the clots as they leave your body, this means you can see the menstrual blood making your period easier to record/making any major differences easy to identify.