The Third-trimester Placental Thickness and Pregnancy Outcomes in Placenta Previa Women

Placenta previa is the placenta overlying the cervical os. Placenta previa is about 1 in 200 pregnancies. The risk factors are the increasing rate of cesarean section and previous uterine surgery. Placenta previa is associated with many adverse complications; the most serious one is related to maternal hemorrhage. The diagnosis of placenta previa is done by trans-abdominal and trans-vaginal ultrasonography, which can document the placental edge's relationship to the internal os. Placenta accreta spectrum disorder is defined when trophoblastic invades the myometrium. The Placenta accreta spectrum can be categorized as: placenta accreta, placenta increta, and placenta percreta.

The clinical utility of placental thickness is an area of ongoing research in placenta previa. Prior studies have demonstrated an association between mid-trimester placental thickness and placenta accreta spectrum. Despite the presence of many studies in characterizing placental thickness, most studies have focused primarily on the placental accreta spectrum lacking information about other fetal and maternal complications. Symptomatic (bleeding) placenta previa is associated with increased maternal and neonatal morbidity and mortality. In addition; the mechanism that involves bleeding is unclear. It is usually related to uterine contractions, cervical effacement, and dilation leading to separation of the placenta from the underlying decidua.