Spontaneous abortion (miscarriage)

Introduction
Abortion is the termination of pregnancy before the period the fetus reaches a viable stage, which is considered to occur at 28th week. However, for international acceptance, the limit of viability is brought down to either 20th week or fetus weighing 500 grams. The term miscarriage, which is mostly used, is synonymous with abortion.

The incidence of abortion is difficult to work out but probably 10% of all pregnancies end in spontaneous abortion.75% abortions occur before the 16th week and of these, about 75% occurs before 8th week of pregnancy.

Abortion is sub classified into the following types:
Spontaneous:

Threatened

Inevitable

Complete

Incomplete

Missed

Septic

Induced

Legal

Illegal(criminal)

What are the causes of abortion?
There are three factors responsible for abortion. They are:

Ovo-fetal factors (60%)

• Chromosomal abnormality (commonest is autosomal trisomy, monosomy) and gross congenital abnormality
• Interference of blood supply to the fetus due to knots or twists in umbilical cord.
• Low attachment or faulty placental formation.
• Twins or hydramnios by rapidly stretching the uterus may cause abortion.

Maternal factors (15%)

• Viral illness such as rubella. Hyper pyrexia may precipitate abortion by inducing uterine irritability.
• Maternal hypoxia and shock due to acute respiratory disease, heart failure, severe anemia.
• Hypertension, chronic nephritis are responsible for abortion by producing placental infarction resulting in fetal anoxia
• Hypothyroidism and diabetes mellitus
• Trauma to the abdomen by blow or fall.
• Psychic: Emotional upset or change may lead to abortion
• Amniocentesis, chorion villus sampling in early months of pregnancy may cause abortion.
• Environmental toxins like lead, arsenic, anesthetic drugs, alcohol, radiation exposure increases the risk of abortion.
• Cervical incompetence and congenital malformations of uterus like bicornuate uterus may be responsible for abortion in the second trimester
• Autoimmune conditions like lupus anticoagulant and antiphospholipid antibodies.
• Blood group in compatibility
• Premature rupture of membranes
• Deficiency of folic acid and Vitamin E

Prenatal factors:

• Defective sperm
• Unknown (25%): In spite of the numerous causes mentioned, it is indeed difficult, in a majority to pinpoint the cause of abortion

What is threatened abortion?
Threatened abortion is a clinical entity where the abortion process has started but has not progressed to a stage from which recovery is impossible.

What are the symptoms in the patient?
The patient who is pregnant complaints of:

• Bleeding per vaginum: The bleeding is usually slight and bright red in color. On rare occasion, bleeding may be brisk. The bleeding usually stops spontaneously.
• Pain: Bleeding is usually painless but there may be mild backache or dull pain in the lower abdomen.

What must be done in case of threatened abortion?
The physician usually does a pelvic examination gently. Routing blood investigations like hemoglobin, blood grouping are done. Ultrasound of the abdomen is done to find the status of the fetus. Serum progesterone value of 25ng/ml or more generally indicates that the fetus (baby) is alive.

The mother is advised bed rest for a few days until the bleeding stops. Prolonged restriction has got no therapeutic value. For relief of pain mild analgesics are given and patient can be sedated if necessary. Mild laxative for bowel evacuation can be taken if needed. Enema should not be given. The patient is advised to preserve the vulval pads for inspection, if anything expels out.

What are the precautions to be followed after discharge from the hospital?
The patient should limit her activities for at least two weeks and avoid heavy work, strenuous exercise and excitement. Coitus is contraindicated during this period. She should come for checkup after one month.

What is inevitable abortion?
Inevitable abortion is the one in which the changes have progressed to a state from where continuation of pregnancy is impossible. The patient, who was having features of threatened abortion, develops the following problems:

• Increased vaginal bleeding
• Increased pain in the lower abdomen
• Examination reveals dilated os of the cervix through which products of conception are felt

What to do incase of inevitable abortion?
The patient should be immediately admitted in the hospital to improve the general condition and to accelerate the process of abortion. Strict asepsis is to be maintained to prevent infection. Morphine should be give for pain. Excessive bleeding is controlled by giving methergine. Shock should be corrected by intravenous fluid and blood transfusion.

If pregnancy is less than 12 weeks, dilatation and curettage is effective. If more than 12 weeks, uterine contraction is accelerated by oxytocin drip and fetus is expelled.

Did you know?
Abortion is the termination of pregnancy before the period the fetus reaches a viable stage, which is considered to occur at 28th week. However, for international acceptance, the limit of viability is brought down to either 20th week or fetus weighing 500 grams. The term miscarriage, which is mostly used, is synonymous with abortion.