Types of Miscarriage (Abortion)
When vaginal bleeding is slight, there is no or mild pain, the cervix is closed and the uterus feels the correct size for date. The diagnosis of "threatened miscarriage" is made. The woman is usually advised bed rest, bleeding and pain may settle down and pregnancy may proceed normally. However, if the bleeding become very heavy, the cervix opens up and the woman complains of intense cramping, the fetus will subsequently pass out; this is called "inevitable abortion". If the fetus and placenta pass out of the womb completely, this is called "complete abortion". If any bits remain inside the cavity of the uterus it is called "incomplete abortion". The patient will then undergo evacuation of retained products of conception (ERPC) under a general anaesthetic. Should any tissue be left in the uterus there is a serious risk of infection. If infection intervenes the term "septic abortion" is used.
Sometimes, the fetus dies in the womb but not expelled, and the term "missed abortion" is used.The diagnosis of all these kinds of miscarriage is made by ultrasound scan, this may show an empty sac, viable pregnancy, retained pregnancy tissue or a dead baby. If the patient has a positive pregnancy test but there are no signs of a pregnancy on the scan, this is called "pregnancy of unknown location". A repeat scan after 7-10 days is necessary to make the diagnosis (RCOG Guidelines).
If the scan shows a gestational sac that is less than 20 mm in diameter and with no obvious yolk sac or a fetus or the scan shows a fetus less than 6 mm in length and no obvious fetal heart beating, this is called "pregnancy of uncertain viability". A repeat scan after 7-10 days is necessary to make the diagnosis (RCOG Guidelines).