Placenta praevia is when the placenta attaches inside the uterus but in a position near or over the cervical opening. Symptoms include vaginal bleeding in the second half of pregnancy. The bleeding is bright red and tends not to be associated with pain. Complications may include placenta accreta, dangerously low blood pressure, or bleeding after delivery. Complications for the baby may include fetal growth restriction.Risk factors include pregnancy at an older age and smoking as well as prior cesarean section, labor induction, or termination of pregnancy. Diagnosis is by ultrasound. It is classified as a complication of pregnancy.For those who are less than 36 weeks pregnant with only a small amount of bleeding recommendations may include bed rest and avoiding sexual intercourse. For those after 36 weeks of pregnancy or with a significant amount of bleeding, cesarean section is generally recommended. In those less than 36 weeks pregnant, corticosteroids may be given to speed development of the babys lungs. Cases that occur in early pregnancy may resolve on their own.It affects approximately 0.5% of pregnancies. After four cesarean sections, however, it affects 10% of pregnancies. Rates of disease have increased over the late 20th century and early 21st century. The condition was first described in 1685 by Paul Portal. Signs and symptoms
Women with placenta previa often present with painless, bright red vaginal bleeding. This commonly occurs around 32 weeks of gestation, but can be as early as late mid-trimester. More than half of women affected by placenta praevia (51.6%) have bleeding before delivery.
An obstetrician may need to divide the anterior lying placenta. In such cases, blood loss is expected to be high and thus blood and blood products are always kept ready. In rare cases, hysterectomy may be required. Complications
Maternal
Antepartum hemorrhage
Malpresentation
Abnormal placentation
Postpartum hemorrhage
Placenta previa increases the risk of puerperal sepsis and postpartum hemorrhage because the lower segment to which the placenta was attached contracts less well post-delivery. Fetal
IUGR (15% incidence)
Hypoxia
Premature delivery
Death

Epidemiology
Placenta previa occurs approximately one of every 200 births globally. It has been suggested that rates of placenta previa are increasing due to increased rate of Caesarian section. Reasons for regional variation may include ethnicity and diet. Africa
Rates of placenta praevia in sub-Saharan Africa are the lowest in the world, averaging 2.7 per 1000 pregnancies. Despite a low prevalence, this disease has had a profound impact in Africa as it is linked with negative outcomes for both the mother and infant. The most common maternal outcome of placenta praevia is extreme blood loss before or after birth (antepartum hemorrhage and postpartum hemorrhage), which is a major cause of maternal and infant mortality in countries like Tanzania. Risk factors for placenta praevia among African women include prior pregnancies, prenatal alcohol consumption, and insufficient gynecologic care. In North Africa placenta praevia rates occur in 6.4 per 1000 pregnancies. Asia
Mainland China has the highest prevalence of placenta praevia in the world, measuring at an average of 12.2 per 1000 pregnancies. Specifically, placenta praevia is most common in Southeast Asia, though the reason for this has not yet been investigated.