Placenta previa is the medical term for a placenta that sits low in the uterus, covering part or all of the cervix. If it is near the cervix, but not over it, it's called a low lying placenta.
When the condition does not self-correct during pregnancy, a C-section may be necessary to prevent dangerous complications in later pregnancy.
Diagnosis of Placenta Previa:
Placenta previa is usually detected during ultrasound, often during the routine ultrasound most practitioners perform around the twentieth week of pregnancy. It may also be revealed as a cause of bleeding during pregnancy.
Risk Factors and Causes of Placenta Previa:
The cause of placenta previa is not known, but according to the American College of Obstetricians and Gynecologists (ACOG), the risk is highest in women who are carrying multiples, who have had more than one pregnancy, or who have had a previous C-section or other uterine surgery.
Symptoms of Placenta Previa:
Placenta previa can exist without symptoms, but it sometimes causes later pregnancy bleeding that may require immediate attention from a healthcare practitioner. Any bleeding in the second or third trimester of pregnancy should be reported to a physician without delay, whether you have been told you have placenta previa or not.
What to Expect With Placenta Previa:
You may be advised to avoid intercourse or strenuous exercise, and your doctor may also advise bed rest and travel restriction if you have experienced bleeding. Delivery by C-section will most likely be recommended if the placenta previa is still present in the third trimester. Moms with placenta previa are sometimes hospitalized in the third trimester, in case they spontaneously go into labor due to the risk that labor could cause severe bleeding.
It's scary to be told that there is anything wrong with your pregnancy that might threaten your baby, but remember that most women with placenta previa are able to carry their babies to term without serious complications. It is good that your doctors are aware of the problem, so they can provide appropriate monitoring. Depending on where you are in your pregnancy, there is a good chance that the placenta previa may correct itself before you give birth. If your placenta previa was diagnosed during the second trimester or earlier, the odds are about 90% that it will self-correct, according to the March of Dimes.
If your placenta previa has been diagnosed after an episode of late pregnancy bleeding, doctors may administer steroid shots to boost the baby's lung maturity in the event that an early delivery might be needed.
ACOG Education Pamphlet AP038. American College of Obstetricians and Gynecologists. Accessed: Aug 2, 2009. http://www.acog.org/publications/patient_education/bp038.cfm
What You Need to Know About Your Placenta. March of Dimes. Accessed: Aug 2, 2009. http://www.marchofdimes.com/pnhec/188_1132.asp