Placenta previa is an abnormal position of the placenta in the uterus during pregnancy
. The former will be situated in the lower part of the uterus, thus too low compared to its natural location. The major risk is bleeding due to a placental abruption, which can occur spontaneously in late pregnancy or complicate childbirth
. Among the factors that cause the formation of a placenta previa are the advanced age of the mother, uterine malformation, a history of uterine problems and multiple pregnancies.
Placenta previa is not generally responsible for any symptoms, and it is often discovered later during an ultrasound. Conventionally, placenta previa presents itself as vaginal bleeding occurring in the last trimester of pregnancy. This uterine bleeding is painless and sometimes appears in the context of sexual intercourse or contractions.
The low position of the placenta in the uterus can be detected by a pregnancy ultrasound monitoring. If bleeding occurs during the last trimester of pregnancy, ultrasound examination is the best way to monitor; a vaginal examination should be avoided because that could trigger a major hemorrhage. The ultrasound confirms the diagnosis and specifies the exact location of the placenta, particularly in relation to the opening of the cervix that can sometimes be completely covered over. Another consideration is frequently done, and is not used for diagnosis, but consist of assessing the status of potential suffering of the fetus by recording the fetal heart rate.
Treatment will depend on a number of criteria: term of pregnancy, amount of bleeding, position of the placenta in the uterus accurately determined by an ultrasound, state of suffering of the fetus or the mother, has labor or childbirth began... Most of the time, hospitalization is required with complete rest and a simple regular surveillance. But a Cesarean may be inevitable if the cervix is completely covered by placenta previa, if the bleeding is excessive, or if the fetus or the mother show signs of poor tolerance.
If we can't prevent placenta previa, its risk factors, however, are known. Women aged over 35 years who use tobacco or who have already had a pregnancy are more likely to be affected.