Prognosis

PP seen in early gestation may migrate into a normal position as pregnancy progresses. This is not true migration but rather differential growth at the upper end of the placenta compared with the lower. About 85% of placentas that are praevia at about 15 to 20 weeks and about one third that are praevia at 20 to 23 weeks will no longer be praevia at the onset of labour.[36][49][50][51][76]

Maternal prognosis

Maternal prognosis is generally good. Women who have an elective and urgent caesarean section are at risk of complications associated with this procedure.[77] Women with PP are at increased risk of receiving blood transfusion (because of preoperative, intra-operative, and postoperative bleeding) with the associated risks (which vary locally).[78] Women are at increased risk of caesarean hysterectomy, although this risk remains low (0.2%).[79][80]

There is an increased risk of PP in subsequent pregnancies, although this risk remains low (<1%).[81][82]

Fetal prognosis

Fetal prognosis is generally good but may be compromised by excessive bleeding and intrauterine growth restriction.[83][84][85]

Neonatal prognosis

Neonatal prognosis is dependent on the degree of prematurity along with the availability of specialist neonatal care.[85][86][87] It is also affected by the degree of pre-delivery bleeding, which may cause neonatal anaemia.[83][84]

There may be a slight increase in the risk of sudden infant death syndrome.[88]

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