[1] Complications may include placenta accreta, dangerously low blood pressure, or bleeding after delivery.

[1] 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.

It is hypothesized to be related to abnormal vascularisation of the endometrium caused by scarring or atrophy from previous trauma, surgery, or infection.

These factors may reduce differential growth of lower segment, resulting in less upward shift in placental position as pregnancy advances.

[18] Traditionally, four grades of placenta previa were used,[15] but it is now more common to simply differentiate between "major" and "minor cases.

[21] Transvaginal ultrasound has superior accuracy as compared to transabdominal one, thus allowing measurement of distance between placenta and cervical os.

In parts of the world where ultrasound is unavailable, it is not uncommon to confirm the diagnosis with an examination in the surgical theatre.

In cases of fetal distress and major degrees (traditional grade III and IV) a caesarean section is indicated.

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.

Risk factors for placenta praevia among African women include prior pregnancies, prenatal alcohol consumption, and insufficient gynecologic care.

[5] Mainland China has the highest prevalence of placenta praevia in the world,[5] measuring at an average of 12.2 per 1000 pregnancies.

Additionally, more cases of placenta praevia are found in women from low-income areas which are linked to insufficient pregnancy care.

According to the socioeconomic demographic in North America, black women are more likely to come from low income areas and are thus more likely to develop placenta praevia.

[5] In Nova Scotia, infants born to pregnant woman who experience placenta praevia have a mortality rate 3–4 times higher than normal pregnancies.

A couple of factors contribute to this rate, including length of time fetus was in the womb and mother's age.

Infants that did survive experienced increased rates of birth defects, breathing problems, and blood abnormalities.