Among women who know they are pregnant, the miscarriage rate is roughly 15-20%.Miscarriage may occur for many reasons, not all of which can be identified. Some of these causes include genetic, uterine, or hormonal abnormalities, reproductive tract infections, and tissue rejection.
Chromosomal abnormalities are found in more than half of embryos miscarried in the first 13 weeks. Chromosomal problems due to a parent's genes are, however, a possibility. This is more likely to have been the cause in the case of a woman suffering repeated miscarriages, or if one of the parents has a child or other relatives with birth defects.
Progesterone deficiency may be another cause. Women diagnosed with low progesterone levels in the second half of their menstrual cycle (luteal phase) may be prescribed progesterone supplements, to be taken for the first trimester of pregnancy
So if you are worried or if this happen several times then check with your gynecologist to know the probable cause through tests and echo.
note if you have any medical condition it may interfere in the pregnancy continuity.