Abortion is defined as the explusion of a fetus before its viable, ussualy before 24 weeks of pregnancy.
Spontaneous abortion, often called miscarriage may occur at any time before 28 weeks, although it is commonest in the first 12 weeks of pregnancy. Of all diagnosed pregnancies 15-20 per cent end in spontaneous abortion.
Spontaneous abortions occurring in early pregnancy are thought to be particulary associated with fetal defects such as chromosomal abnormalities. They have also attributed to a lack of progesterone secretion during the developing the developing pregnancy, abnormalities of the shape of uterine cavity and maternal disorders such as a diabetes mellitus, diseases of the thyroid gland and problems with immune system. An incomplete response of the maternal immune system to pregnancy seems of particular importance in women who suffer recurrent miscarriages, defined as three or more spontaneous abortions.
Factors such as increased maternal age a high number previous pregnancies and smoking predispose to spontaneous abortion.
Ultrasound scans have altered the management of abortions. These make it possible to distinguish between threatened miscarriages, where the women have experienced some vaginal bleeding, but the fetus is alive, inevitable abortion, where the neck of the womb has started to open up, incompleted abortion, where part of the fetus or placenta is retained and complete abortions. Whereas bed rest may be useful is treating threatened abortions, an inevitable or incomplete abortion will normally or incomplete will normally require evalution of the uterus and complete miscarriage should require no treatment at all.
Evaation of the uterus involves administering a general anaesthetic, gentle dilatation of the neck of the womb and removal of the remaining products of the pregnancy.
Maternal factors are thought to account more often to late abortions. These include an inappropriately early opening of the neck of the womb, structural abnormalities and infections of the uterus.
Ultrasound scan is important to assess the condition of the intrauterine fetus. If the fetus appears normal uterine contractions may be suppressed with drugs.
In cases of cervical incompetence, it mayb be possible to close the cervical canal with sutureich is removed at 38 gestation.
Therapeutic abortion Before this interventional procedure can take place, 2 doctors must agree that the continuation of the pregnancy would involve risk, greated than if the pregnancy were terminated, of injury to the physical or mental health of the mother.