Miscarriage refers to the premature end of a pregnancy before
the developing baby is able to survive outside the womb.
Miscarriage can occur during the first or second trimester,
before 20 weeks. Most occur in the first 12 weeks of pregnancy.
They often are unexpected and isolated events. About 15%-20% of
recognized pregnancies end this way. Fetus in First Trimester
Copyright © Nucleus Medical Media, Inc. Miscarriages often occur
for the following reasons: - Chromosomal abnormalities (common
cause) Abnormalities in the uterine tract (eg, - Hormonal
problems (eg, not having enough progesterone, a female hormone
needed to support pregnancy) - Factors related to the immune
system (eg, may cause blood-clotting problems or rejection of
the fetus) In some cases, the cause is unknown. Factors that may
increase the risk of miscarriage include: - Having an infection
- Being older (maternal age of 35 years or older) - Smoking,
drinking alcohol, or using - Taking certain prescribed medicines
- Being exposed to certain e