What is a miscarriage?
A miscarriage (spontaneous abortion) is any pregnancy that is non-viable (wherein the fetus cannot survive) or is born before the 20th week of pregnancy.
What are the causes of miscarriage?
- Genetic (chromosomal) abnormalities represent the single most frequent reason for miscarriages.
- Sometimes it is because you have some other illness during your early pregnancy (probably an infection causing a fever).
- Infection of the uterus by bacteria and viruses has been associated with miscarriages.
- Certain medications, alcohol and smoking, can increase the risk of miscarriage.
- After the first three months of pregnancy you are unlikely to have a miscarriage- but if you do, it might sometimes be because the neck of your womb is weak.
- It is speculated that abnormally low levels of female sex hormone Progesterone could be associated with increased incidence of miscarriage.
- Medical causes like Diabetes and Thyroid disease, can be associated with recurrent miscarriage.
How common is it?
Miscarriages are amazingly common. Miscarriage occurs in about 15-20% of all recognized pregnancies, and usually occurs before the 13th week of pregnancy.
What are the symptoms?
The main symptoms of abortion are bleeding through the vagina, which may or may not be associated with cramping and pain in the lower abdominal area. The extent of bleeding may vary from slight and painless bleeding in case of a threatened abortion to severe bleeding with acute pain, in case of an ineveitable abortion.
When should I consult my doctor?
You should see your doctor if you have any vaginal bleeding in pregnancy. If the bleeding is heavy, and specially if there are clots or you have a lot of pain, you should talk to your doctor immediately. He or she will advise you about what to do next.
What tests are done to identify the cause of miscarriage?
Since the chance of having a normal pregnancy subsequent to an isolated miscarriage is 80-90%, a detailed investigation is not undertaken. Recurrent miscarriages however warrant a detailed workup.
- Blood testing can be done to identify chromosomal abnormalities.
- The blood can also be tested for hormone levels to assess the degree to which hormone imbalance could play a role.
- Blood samples can also be tested for the antibodies that interfere with implantation and growth of the fertilized egg.
Internal Examination :
- Evaluation of the uterus includes cultures taken from the cervix and vagina for infections.
- Ultrasound scan of the womb, an MRI or CT scan could be used to evaluate the structure of the uterus and the uterine cavity.
- The internal uterine cavity can be further assessed using direct vision through an instrument called a hysteroscope.
Even after extensive testing, the cause can not be ascertained in upto 50% of cases.
Revision date: July 4, 2011
Last revised: by Jorge P. Ribeiro, MD