Placenta Previa: Fetal Growth and Pregnancy Outcome

• Placenta previa is described as suboptimal placental implantation over or very near the internal cervical os.

• Only 1 in 200 pregnancies are complicated by persistent placenta previa at delivery.

• The incidence of placenta previa appears to increase in a dose-dependent manner such that increasing the number of prior cesarean deliveries is associated with increasing incidence rates of placenta previa in subsequent pregnancies.

• The pathophysiology of placenta previa is still unclear. It appears to be associated with endometrial damage and uterine wall scarring, which may interfere with the normal process of placental implantation and development.

• Other risk factors include:

  1. Previous spontaneous and elective pregnancy terminations

  2. Previous uterine surgeries

  3. Parity

  4. Advanced maternal age

  5. Smoking

  6. Cocaine use

  7. Multiple gestations

  8. In vitro fertilization

  9. Prior placenta previa

• Pregnancies complicated by placenta previa have been associated with adverse maternal and neonatal outcomes.

• Adverse neonatal outcomes:

  1. Preterm and early-term deliveries

  2. Prematurity

  3. Low Apgar scores

  4. Fetal and neonatal death 

• Adverse maternal outcomes:

  1. Maternal intrapartum and postpartum hemorrhage

  2. Sepsis

  3. Hysterectomy

• More placental vascular supply lesions, higher rate of small-for-gestational-age (SGA), and worse neonatal outcome characterized pregnancies with placenta previa in the current study. These findings may suggest that abnormal placentation is accompanied by suboptimal implantation that interferes with fetal growth.

source:

https://www.nature.com/articles/jp2016140

https://doi.org/10.1038/jp.2016.140