Miscarriage Overview

A miscarriage (also termed spontaneous abortion) is any pregnancy that spontaneously ends before the fetus can survive. Any vaginal bleeding, other than spotting, during early pregnancy is considered a threatened miscarriage. Vaginal bleeding is very common in early pregnancy. About one out of every four pregnant women has some bleeding during the first few months. About half of these women stop bleeding and complete a normal pregnancy.

• Threatened miscarriage - Vaginal bleeding during early pregnancy. The bleeding and pain with threatened miscarriage are usually mild and the cervical os (the mouth of the womb) is closed. Your health care provider will be able to determine if the cervical os is open upon performing a pelvic exam. Typically, no tissue is passed from the womb. The womb and fallopian tubes may be tender.
  
  
• Inevitable miscarriage - Vaginal bleeding along with opening of the cervical os. In this situation, vaginal bleeding is present, and the mouth of the womb is open (dilated). Bleeding is usually more severe, and abdominal pain and cramping often occur.
  
  
• Incomplete miscarriage - Expulsion of some, but not all, of the products of conception before the twentieth week of pregnancy. With incomplete miscarriage, the bleeding is heavier, and abdominal pain is almost always present. The mouth of the womb is open, and the pregnancy is being expelled. Ultrasound would show some material still remaining in the womb.
  
  
• Complete miscarriage - Expulsion of all products of conception from the womb including fetus and placental tissues. Complete miscarriage is just as it sounds. Bleeding, abdominal pain, and the passing of tissue have all occurred, but the bleeding and pain have usually stopped. If you can see the fetus, you have miscarried. Ultrasound shows an empty womb.

A miscarriage occurs when a pregnancy ends without obvious cause before the fetus is capable of survival, typically corresponsing to the twentieth to 22^nd week. This time is measured from the first day of your last menstrual period. Miscarriage is a common complication of pregnancy. It can occur in up to 20% of all recognized pregnancies. This ending of pregnancy is called a spontaneous abortion. In the medical field, the term abortion is often used to describe a miscarriage.

from emedicinehealth.com
http://our-medical-center.blogspot.com/2008/01/miscarriage-overview.html