Miscarriage is defined by the World Health Organization as the removal or ejection of a fetus or embryo weighing 500g or less from the womb of a mother before 23 weeks of pregnancy. On the whole, about 3 in 20 pregnancies end in miscarriage and the frequency tends to increase as the age of the mother increases.

Miscarriage and abortion are a couple of terms that are used in place of each other to describe the loss of a pregnancy in the initial trimesters. Having said that, generally, miscarriage is attributed to the accidental or unplanned loss of pregnancy whereas abortion is used for a planned termination of pregnancy.

Accidental miscarriage is typically portrayed by some kind of vaginal bleeding that can take place with or without pain. The portrayal may vary from one individual to another based on its types. When an expecting woman in her early trimesters suffering from vaginal bleeding visits the doctor, the physician generally suggests an ultrasound scan to confirm the diagnosis. On a few occasions, the fetus has not thoroughly aborted but the pregnancy is at risk and this situation is called as threatened miscarriage. If a fetal heartbeat is noted in the ultrasound scan, it means that the pregnancy is still viable. Almost one in every three cases of threatened miscarriages tends to progress and results in a terminated pregnancy. Surgery may be resorted to in such cases.

Women who have suffered more than three successive spontaneous or accidental miscarriages, investigation should be conducted to determine the actual cause. The risk of miscarriage tends to decrease substantially with each passing week and as the seventh week of pregnancy is reached, less than 5% of pregnancy may be spontaneously aborted or terminated.