Some people may experience bleeding or clots during early pergnancy. This can be due to implantation bleeding (which is normal), cervical changes (also normal), infections (call your doctor), or other medical reasons like miscarriage.
Miscarriage blood clots look a lot like normal period blood clots. If you are experiencing blood clots during your pregnancy whether its is in your first or last trimester it is always best to call a doctor just to be sure that everything (such as the baby) is ok and healthy.
I hope this helps :)