Miscarriage in Pregnancy
Written by Dr.M.D.Mazumdar, MD
Miscarriage is also known as spontaneous abortion. It is defined as the expulsion or extraction from its mother of a foetus or embryo weighing less than 500 grams or 20 completed weeks of gestation. Loss of pregnancy after 20 weeks is considered preterm delivery.
About 20% of all pregnancies end in abortion. Since many pregnancies end at or around the time of implantation, i.e. before the first missed menstrual period, they go unnoticed. About 80% of all recognized abortions occur during the 2nd or 3rd months of pregnancy. The others occur during the remaining months up to 20 weeks.
Causes of Miscarriage / Abortion
A miscarriage may be spontaneous or induced.
A Spontaneous Miscarriage can be due to:
Fault in the Embryo: Embryos with chromosomal defects are seen in about two-thirds of all early abortions. Chromosomal defects may also be present in the placenta (for example, Hydatidiform mole or Molar pregnancy) causing death of the foetus.
Fault in the Maternal Environment:
- Infections by toxoplasma (common) or by Listeria monocytogenes.
- Hormonal deficiencies as in progesterone deficiency in corpus luteum defect, or in hyperthyroidism or hypothyroidism.
- Cervical Incompetence
- Rh-ve pregnancy
- ABO incompatibility
- Some maternal diseases which cause high fever.
- Uterine fibroid causing improper implantation of the placenta
- Physical trauma, e.g. a blow on the abdomen or that caused by a fall.
- Surgical trauma due to any operation.
- Congenital malformations of the uterus like hypoplastic uterus, unicornuate, bicornuate uterus, septate uterus etc.
Abortions can occur in two ways:
- Death of the Embryo: Death of the embryo or the fetus can be the first event to occur followed by its expulsion from the uterus. This is usually seen in very early pregnancies.
- Abnormal Uterine Activity: In these type of abortions, the main event is abnormal uterine activity, causing the uterus to expel a healthy foetus. This is usually a feature of abortions in the second trimester (after 13 completed weeks of pregnancy).
Signs and Symptoms of Abortion / Miscarriage
Pain and Bleeding: The chief symptoms of abortion are pain and bleeding. Whether pain occurs first or bleeding will depend on whether the abortion is due to death of the foetus or abnormal uterine activity.
Pain occurs when the uterus starts to contract to expel the now unwanted product of gestation. It is usually intermittent and is often described as 'colicky'. Pain continues to increase until the product is expelled from the uterus. If the product is expelled completely, pain may cease completely. But if any amount of the product is retained, there may be continued pain or at least some discomfort till the uterus is completely empty. Surgical intervention may be needed to empty out the uterus.
A mild haemorrhagic discharge, somewhat similar to the lochia seen after childbirth continues for a few days, then gradually ceases.
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Clinical Types of Miscarriage / Abortion
There are different clinical types of miscarriages or abortions:
Threatened Abortion/Miscarriage
This type of abortion starts with pain that occurs as a result of abnormal uterine activity. The embryo is usually alive. There will be a crampy pain that gradually increases in severity. A mild bleeding or blood stained vaginal discharge can occur. The cervix of the uterus however remains closed. There is a possibility of continuation of the pregnancy on proper and timely management.
Treatment :The aim of treatment is to try and conserve the pregnancy by decreasing the uterine contractions. Complete bed rest, uterine relaxants like isoxsuprine hydrochloride or ritodrine and sedating the patient are various methods used to prevent uterine contraction.
Progesterone supplements are given if progesterone deficiency is suspected to be the cause of the threatened abortion. Human Chorionic Gonatrophin(HCG) injections can also be prescribed to support the pregnancy. But the main and most effective treatment is complete bed rest of the patient.
Inevitable Abortion / Miscarriage
If the treatment of threatened abortion is not adequate or timely, the abortion may become inevitable. In this type of abortion, besides pain and bleeding there is also dilation of the cervix of the uterus and the process of expulsion of the fetus cannot be stopped.
Treatment: The aim of treatment is to prevent further pain and bleeding by emptying the uterus as early as possible. Further dilation of the cervix and curettage (D&C) of the uterine cavity have to be carried out. Medicines like misoprostol can also be prescribed to increase the uterine contracitons and speed up the miscarriage. If bleeding is severe, supportive treatment like IV fluids and blood transfusion may also become necessary.
Treatment: To evacuate the uterus completely by D&E (dilation and evacuation), and to prevent infection.
Treatment: Supportive, with antibiotics, pain-relieving tablets etc.
There may mild brown or dirty vaginal discharge. Frank bleeding is uncommon but may sometimes occur.
On further questioning, she may reveal that there had been some episodes of pain or even blood stained discharge earlier that cleared up spontaneously. But sometimes there may not be any pain or bleeding at any time.
On examination, the size of the uterus will be found to be smaller than the duration of pregnancy suggested by the number of missed periods.
Treatment: To remove the dead product as early as possible and to prevent infection.
Causes of Habitual Abortion / Miscarriage:
Treatment: Treatment of habitual abortion should be started when the woman is in a non-pregnant state. Thorough investigations to identify the cause is carried out - blood tests for hormonal levels and for infections, blood glucose level, USG for uterine causes and to identify cervical incompetence and for uterine causes etc.
Once a new pregnancy has started, treatment is as per the identified cause. If cervical incompetence is the cause, the cervical opening is sutured (tied up) until the 37th week of gestation. Hormonal deficiencies and infections are treated by medicines and bed rest.
Treatment: Active support with high-grade antibiotics and anti-inflammatory drugs are given. An IV line may be necessary to provide fluids and nutrition to the patient.
If the infection is restricted to the uterus, careful evacuation of the products are carried out.
If there is evidence of spread of infection outside the uterus, evacuation is carried out only after the infection has been controlled. However if it is deemed that the infection cannot be controlled unless the source of infection, i.e. the products are removed, then careful evacuation of the uterus may be carried out, sometimes under anaesthesia.
The deliberate induction of abortion on grounds of safety for the maternal life and health is termed Medical termination of Pregnancy.
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Incomplete Abortion / Miscarriage
Occasionally, some part of the gestational tissue (embryo+early placenta+membranes) may be retained within the uterus during the process of abortion while other parts may be expelled. This is then called an incomplete abortion or miscarriage. An ultrasound can help in the diagnosis of retained products.
Complete Abortion / Miscarriage
When the embryonic and placental components have been expelled completely, it is called a complete abortion. Normally, once complete abortion occurs, there is complete cessation of pain and bleeding. An ultrasonography becomes necessary to confirm that the uterus is indeed empty.
Missed Abortion / Miscarriage
This is a type of miscarriage where the product is dead but retained inside the uterus and the patient is unaware that a miscarriage has occurred. The patient usually comes with a complaint of missed menstrual periods for a month or two.
An USG is necessary to confirm the diagnosis.
Habitual or Recurrent Abortion / Miscarriage
When three or more abortions or miscarriages have occurred consecutively and spontaneously, the process is termed habitual miscarriage or recurrent miscarriage.
Septic Abortion
This is a type of abortion where there is sepsis or infection of the uterus and its contents. The underlying abortion is usually incomplete, but sometimes, inevitable or threatened. The patient suffers from high fever and looks toxic. There is foul-smelling vaginal discharge which may or may not be blood stained. Extra-uterine spread of infection can occur. It is more commonly seen in abortions which are carried out by unauthorised and incompetent persons in dirty surroundings.
Medical termination of Pregnancy
(Syn: therapeutic abortion)