Miscarriage is a pregnancy that ends spontaneously before 20 weeks. The loss of a fetus after the 20th week of pregnancy is called a stillbirth.

Miscarriage is very common. In fact, it has been estimated that half of all pregnancies end in an early miscarriage that occurs before the first period would have been missed, when most women do not yet know they are pregnant. Of pregnancies that make it past this point, up to 15 per cent result in a miscarriage, mostly during the first trimester. Sometimes your doctor or nurses may refer to your miscarriage as a spontaneous abortion. Abortion is the common medical name for all pregnancies that end before 20 weeks — both miscarriages and terminations.

Why does miscarriage occur?
Most miscarriages occur because something went wrong during or soon after conception. many reasons are there behind this. Here is a list of some reasons.

• In many cases the part of the pregnancy that grows into the baby fails to develop. This may be due to genetic abnormalities in the baby's cells.

• The fertilised egg may not attach itself to the wall of the uterus or attaches in the wrong place.

• enough of the hormones may not b produced in the mother's body that support a pregnancy, such as progesterone.

• Something may be wrong with the placenta.

• The placenta may get rejected by the mother's immune system.

• The mother may have an underlying medical condition, such as uncontrolled diabetes, a thyroid problem, or a tendency towards blood clots.

• She may have a deformed uterus, a weak cervix or an intra-uterine contraceptive device (IUD) inside the uterus.

• Exposure to some environmental chemical pollutants, including cigarette smoke, can increase the risk of miscarriage.

• With age and with the number of previous pregnancies the rik of miscarriages increases.