One common type of miscarriage is a blighted ovum. In this condition, known also as an anembryonic pregnancy, a fertilized egg implants into the uterine wall but does not develop. Cells develop to form the gestational sac, which continues to grow, but the fetus does not grow. A blighted ovum usually occurs within the first trimester and most often even before a woman knows she is pregnant.
Frequency and Causes
It is estimated that 10-25% of all clinically recognized pregnancies end in miscarriage, and that a blighted ovum accounts for approximately 50% of all first trimester miscarriages.
A blighted ovum is usually caused by chromosomal abnormalities. When a woman's body detects abnormal chromosomes in the fetus, it naturally aborts the pregnancy since it knows the fetus will not develop into a healthy baby. Research indicates that a blighted ovum can result from a problem with the egg or the sperm, or be caused by abnormal cell division.
Generally, a blighted ovum is considered a one-time event and does not mean that if you have suffered one blighted ovum that you are at risk for another. However, the possibility of a miscarriage is a risk in all pregnancies.
Detection and Prevention
In most cases a blighted ovum occurs very early in pregnancy, before a woman is even aware she is pregnant. In other instances a woman may have normal indicators of being pregnant, such as a missed or late period or a positive pregnancy test. She may notice vaginal spotting or bleeding and have mild abdominal cramps.
However, since hormone levels continue to rise as they would in a normal pregnancy, a woman may continue to believe that she still pregnant, and a diagnosis is usually not made until an ultrasound test reveals an empty sac or an empty womb.
Unfortunately, nothing can be done to prevent a blighted ovum. Fortunately, it is rare that a woman will experience more than one blighted ovum. If you have had multiple first trimester miscarriages, however, you may want to consider genetic testing. In addition, some studies indicate that low progesterone may be a factor in early pregnancy loss and that progesterone supplements have lowered miscarriage risk for some women. Therefore, if you suspect that progesterone may be a problem, you can ask your doctor to test your progesterone levels early in the pregnancy.
Natural Miscarriage vs. D&C
After a miscarriage the main goal is to prevent hemorrhaging and infection. The earlier you are in a pregnancy when you suffer a miscarriage, the more likely it is that your body will expel the fetal tissue by itself and you will not require further medical procedures, such as a D&C (dilation and curettage).
Most doctors do not recommend a D&C for an early pregnancy loss. In general, a woman can safely wait for nature to take its course without fear of infection provided her vital signs are stable and that she does not have a fever or experience excessive pain or bleeding.