Definition Placenta previa is a condition wherein the placenta of a pregnant woman is implanted abnormally in the uterus. It accounts for the most incidents of bleeding in the third trimester of pregnancy. Pathophysiology The placenta implants on the lower part of the uterus. The lower uterine segment separates from the upper segment as the cervix starts to dilate. The placenta is unable to stretch and accommodate the shape of the cervix, resulting in bleeding. Risk Factors Placenta previa is dangerous if not detected early. However, it is also highly preventable once you get to know the risk factors. Advanced maternal age. Women who are over the age of 35 years old are at an increased risk of developing placenta previa. Multiple gestations. The uterus which has accommodated more than one fetus has an increased risk for placenta previa. Increased parity. Women who have given birth to a lot of children have an increased chance of having placenta previa. Past caesarean births. Giving birth via caesarean delivery predisposes the woman toplacenta previa on her next childbearing. Past uterine curettage. Scars from a past curettage can affect the implantation of the uterus and lead to placenta previa. Types These types of placenta previa are classified according to the degree of the opening that is covered by the placenta. Low lying placenta. The placenta implants in the lower portion instead of the upper portion of the uterus. Marginal implantation. The placenta’s edge is nearing the cervical os. Partial placenta previa. A portion of the cervical os is already covered by the placenta. Total placenta previa. The placenta occludes the entire cervical os. Signs and Symptoms The following signs and symptoms for placenta previa must be detected immediately by the health care providers to avoid risking the life of the fetus. Bright red bleeding. When the placenta is unable to stretch to accommodate the shape of the cervix, bleeding will occur suddenly that could frighten the woman. Painless. Bleeding in placenta previa is not painless and may also stop as abruptly as it had begun. Diagnostic Tests To diagnose placenta previa, the patient must undergo the following diagnostic procedure. Ultrasound. Early detection of placenta previa is always possible through ultrasonography. It is the most common and initial diagnostic test that could confirm the diagnosis. Medical Management Medical interventions are necessary to ensure that the safety of both mother and fetus are still intact. Intravenous therapy. This would be prescribed by the physician to replace the blood that was lost during bleeding. Avoid vaginal examinations. This may initiate hemorrhage that is fatal for both the mother and the baby. Attach external monitoring equipment. To monitor the uterine contractions and record fetal heart sounds, an external equipment is preferred than the internal monitoring equipment. Surgical Management Surgical interventions are carried out once the condition of both the mother and the fetus has reached a critical stage and their lives are exposed to undeniable danger. Cesarean delivery. Although the best way to deliver a baby is through normal delivery, if theplacenta has obstructed more than 30% of the cervical os it would be hard for the fetus to get past the placenta through normal delivery. Cesarean birth is then recommended by the physician. Source
