Spontaneous abortion is the pregnancy at 28 weeks before the self-termination, fetal weight <1000g were. This definition is based on the provisions of the World Health Organization in 1966 enacted the current abortion time limit, on the abortion time limit existence to some controversy, some countries will set the time limit for abortion 25 weeks, or even 20 weeks, because in developed countries more than 20 weeks gestational age, 600 ~ 700g weight of newborns receive adequate treatment because there is also chance of survival. However, the actual situation in accordance with domestic, will continue to set the time limit for abortion before 28 weeks.
Clinical abortions will happen at 12 weeks pregnant former is called an early abortion; happen at 12 weeks, the latter referred to as late miscarriage. Spontaneous abortion is a common gynecological disease, if treatment is not timely, probably left over from genital inflammation, injury, or pregnant women because of bleeding endanger health or even life-threatening; In addition, spontaneous abortion is also easy with certain gynecological diseases confusion, attention should be paid to identify .
Abortion is the human reproduction process of natural selection for someone young (20 to 29 years old), healthy women of childbearing age in 1000 of the natural cycle of pregnancy outcome to do the statistics found at all of pregnancy, about 28.7% ended in spontaneous abortion is because of the Most miscarriages happen in the implantation period and pre-clinical development of embryos sometimes just to stop the performance for extended periods or menorrhagia, both patients and physicians can not be identified. And in the clinical pregnancy can be confirmed, at least 8.6% of spontaneous abortion happened.