Spontaneous abortion (SAB), or miscarriage, is the term used for a pregnancy that ends on its own, within the first 20 weeks of gestation. The medical name spontaneous abortion (SAB) gives many women a negative feeling, so throughout this article we will refer to any type of spontaneous abortion or pregnancy loss under 20 weeks as miscarriage.
Miscarriage is the most common type of pregnancy loss, according to the American College of Obstetricians and Gynecologists (ACOG). Studies reveal that anywhere from 10-25% of all clinically recognized pregnancies will end in miscarriage. Chemical pregnancies may account for 50-75% of all miscarriages. This occurs when a pregnancy is lost shortly after implantation, resulting in bleeding that occurs around the time of her expected period. The woman may not realize that she conceived when she experiences a chemical pregnancy.
Most miscarriages occur during the first 13 weeks of pregnancy. Pregnancy can be such an exciting time, but with the great number of recognized miscarriages that occur, it is beneficial to be informed about miscarriage, in the unfortunate event that you find yourself or someone you know faced with one.
There can be many confusing terms and moments that accompany a miscarriage. There are different types of miscarriage, different treatments for each, and different statistics for what your chances are of having one. The following information gives a broad overview of miscarriage. This information is provided to help equip you with knowledge so that you might not feel so alone or lost if you face a possible miscarriage situation. As with most pregnancy complications, remember that the best person you can usually talk to and ask questions of is your health care provider.
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Why do miscarriages occur?
The reason for miscarriage is varied, and most often the cause cannot be identified. During the first trimester, the most common cause of miscarriage is chromosomal abnormality – meaning that something is not correct with the baby’s chromosomes. Most chromosomal abnormalities are the cause of a damaged egg or sperm cell, or are due to a problem at the time that the zygote went through the division process. Other causes for miscarriage include (but are not limited to):
- Hormonal problems, infections or maternal health problems
- Lifestyle (i.e. smoking, drug use, malnutrition, excessive caffeine and exposure to radiation or toxic substances)
- Implantation of the egg into the uterine lining does not occur properly
- Maternal age
- Maternal trauma
Factors that are not proven to cause miscarriage are sex, working outside the home (unless in a harmful environment) or moderate exercise.
What are the chances of having a Miscarriage?
For women in their childbearing years, the chances of having a miscarriage can range from 10-25%, and in most healthy women the average is about a 15-20% chance.
- An increase in maternal age affects the chances of miscarriage
- Women under the age of 35 yrs old have about a 15% chance of miscarriage
- Women who are 35-45 yrs old have a 20-35% chance of miscarriage
- Women over the age of 45 can have up to a 50% chance of miscarriage
- A woman who has had a previous miscarriage has a 25% chance of having another (only a slightly elevated risk than for someone who has not had a previous miscarriage)
What are the Warning signs of Miscarriage:
If you experience any or all of these symptoms, it is important to contact your health care provider or a medical facility to evaluate if you could be having a miscarriage:
- Mild to severe back pain (often worse than normal menstrual cramps)
- Weight loss
- White-pink mucus
- True contractions (very painful happening every 5-20 minutes)
- Brown or bright red bleeding with or without cramps (20-30% of all pregnancies can experience some bleeding in early pregnancy, with about 50% of those resulting in normal pregnancies)
- Tissue with clot like material passing from the vagina
- Sudden decrease in signs of pregnancy
The different types of Miscarriage:
Miscarriage is often a process and not a single event. There are many different stages or types of miscarriage. There is also a lot of information to learn about healthy fetal development so that you might get a better idea of what is going on with your pregnancy. Understanding early fetal development and first trimester development can help you to know what things your health care provider is looking for when there is a possible miscarriage occurring.
Most of the time all types of miscarriage are just called miscarriage, but you may hear your health care provider refer to other terms or names of miscarriage such as:
Threatened Miscarriage: Some degree of early pregnancy uterine bleeding accompanied by cramping or lower backache. The cervix remains closed. This bleeding is often the result of implantation.
Inevitable or Incomplete Miscarriage: Abdominal or back pain accompanied by bleeding with an open cervix. Miscarriage is inevitable when there is a dilation or effacement of the cervix and/or there is rupture of the membranes. Bleeding and cramps may persist if the miscarriage is not complete.
Complete Miscarriage: A completed miscarriage is when the embryo or products of conception have emptied out of the uterus. Bleeding should subside quickly, as should any pain or cramping. A completed miscarriage can be confirmed by an ultrasound or by having a surgical curettage (D&C) performed.
Missed Miscarriage: Women can experience a miscarriage without knowing it. A missed miscarriage is when embryonic death has occurred but there is not any expulsion of the embryo. It is not known why this occurs. Signs of this would be a loss of pregnancy symptoms and the absence of fetal heart tones found on an ultrasound.
Recurrent Miscarriage (RM): Defined as 3 or more consecutive first trimester miscarriages. This can affect 1% of couples trying to conceive.
Blighted Ovum: Also called an anembryonic pregnancy. A fertilized egg implants into the uterine wall, but fetal development never begins. Often there is a gestational sac with or without a yolk sac, but there is an absence of fetal growth.
Ectopic Pregnancy: A fertilized egg implants itself in places other than the uterus, most commonly the fallopian tube. Treatment is needed immediately to stop the development of the implanted egg. If not treated rapidly, this could end in serious maternal complications.
Molar Pregnancy: The result of a genetic error during the fertilization process that leads to growth of abnormal tissue within the uterus. Molar pregnancies rarely involve a developing embryo, but often entail the most common symptoms of pregnancy including a missed period, positive pregnancy test and severe nausea.
Treatment of Miscarriage:
The main goal of treatment during or after a miscarriage is to prevent hemorrhaging and/or infection. The earlier you are in the pregnancy, the more likely that your body will expel all the fetal tissue by itself and will not require further medical procedures. If the body does not expel all the tissue, the most common procedure performed to stop bleeding and prevent infection is a dilation and curettage, known as a D&C. Drugs may be prescribed to help control bleeding after the D&C is performed. Bleeding should be monitored closely once you are at home; if you notice an increase in bleeding or the onset of chills or fever, it is best to call your physician immediately.
Prevention of Miscarriage:
Since the cause of most miscarriages is due to chromosomal abnormalities, there is not much that can be done to prevent them. One vital step is to get as healthy as you can before conceiving to provide a healthy atmosphere for conception to occur.
- Exercise regularly
- Eat healthy
- Manage stress
- Keep weight within healthy limits
- Take folic acid daily
- Do not smoke
Once you find out that you are pregnant, again the goal is to be as healthy as possible, to provide a healthy environment for your baby to grow in:
- Keep your abdomen safe
- Do not smoke or be around smoke
- Do not drink alcohol
- Check with your doctor before taking any over-the-counter medications
- Limit or eliminate caffeine
- Avoid environmental hazards such as radiation, infectious disease and x-rays
- Avoid contact sports or activities that have risk of injury
Unfortunately, miscarriage can affect anyone. Women are often left with unanswered questions regarding their physical recovery, their emotional recovery and trying to conceive again. It is very important that women try to keep the lines of communication open with family, friends and health care providers during this time.
Some helpful web sites that address miscarriage and pregnancy loss include:
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Compiled using information from the following sources:
Current Obstetric & Gynecologic Diagnosis & Treatment Ninth Ed. DeCherney, Alan H., et al, Ch. 14.
MedlinePlus [Internet]. Bethesda (MD): National Library of Medicine (US); [updated 2006 Feb 23]. Pregnancy Loss; [updated 2006 Feb 22; reviewed 2006 Feb 7; cited 2006 Feb 23]. Available from: http://www.nlm.nih.gov/medlineplus/pregnancyloss.html
Planning Your Pregnancy and Birth Third Ed. The American College of Obstetricians and Gynecologists, Ch. 15.
Williams Obstetrics Twenty-Second Ed. Cunningham, F. Gary, et al, Ch. 9.